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Project Euler with Befunge

A lot of you probably know Project Euler.
For those who don't here a short explanation: Project Euler is a collection of mathematical/programming problems. Most problems consist of finding a single number and are solved by writing a program in the programming language of your choice.

Most people solve these by using normal languages like C, Java, Phyton, Haskell etc. But you can also go a step further and try solving it with a little bit more exotic languages.

So here are my solutions written in Befunge

Note:
Similar to most Befunge content on this site I only used the Befunge-93 instruction-set but ignored the 80x25 size restriction. (Even so most programs here don't get this big.)

Number Title Time Size Solution (hover to reveal)
1 Multiples of 3 and 5
62ms
30x5
Bef-93
233,168
2 Even Fibonacci numbers
62ms
26x5
Bef-93
4,613,732
3 Largest prime factor
9.55s
55x4
Bef-93
6,857
4 Largest palindrome product
1min 17s
71x6
Bef-93
906,609
5 Smallest multiple
47ms
73x6
Bef-93
232,792,560
6 Sum square difference
7.35s
72x16
Bef-93
25,164,150
7 10001st prime
7.63s
1000x156
Bef-98
104,743
8 Largest product in a series
234ms
116x29
Bef-98
23,514,624,000
9 Special Pythagorean triplet
6min 34s
79x7
Bef-93
31,875,000
10 Summation of primes
1min 7s
2000x1007
Bef-98
142,913,828,922
11 Largest product in a grid
78ms
151x31
Bef-98
70,600,674
12 Highly divisible triangular number
7.57s
1000x170
Bef-98
76,576,500
13 Large sum
78ms
59x113
Bef-98
5,537,376,230
14 Longest Collatz sequence
11min
51x5
Bef-93
837,799
15 Lattice paths
47ms
78x27
Bef-98
137,846,528,820
16 Power digit sum
4.23s
60x14
Bef-93
1,366
17 Number letter counts
47ms
48x15
Bef-93
21,124
18 Maximum path sum I
16ms
120x16
Bef-98
1,074
19 Counting Sundays
546ms
72x12
Bef-93
171
20 Factorial digit sum
265ms
101x6
Bef-98
648
21 Amicable numbers
1min 42s
400x33
Bef-98
31,626
22 Names scores
16min
109x5164
Bef-98
871,198,282
23 Non-abundant sums
32min
400x88
Bef-98
4,179,871
24 Lexicographic permutations
31ms
61x8
Bef-93
2,783,915,460
25 1000-digit Fibonacci number
1min 56s
123x28
Bef-98
4,782
26 Reciprocal cycles
4.48s
100x16
Bef-98
983
27 Quadratic primes
6.24s
600x162
Bef-98
-59,231
28 Number spiral diagonals
15ms
54x2
Bef-93
669,171,001
29 Distinct powers
23min
248x59
Bef-98
9,183
30 Digit fifth powers
7.33s
59x8
Bef-93
443,839
31 Coin sums
47s
60x11
Bef-93
73,682
32 Pandigital products
7.19s
166x21
Bef-98
45,228
33 Digit canceling fractions
109ms
67x18
Bef-93
100
34 Digit factorials
1min 20s
45x7
Bef-93
40,730
35 Circular primes
27s
2000x516
Bef-98
55
36 Double-base palindromes
172ms
78x8
Bef-93
872,187
37 Truncatable primes
20s
2000x514
Bef-98
748,317
38 Pandigital multiples
624ms
169x6
Bef-98
932,718,654
39 Integer right triangles
827ms
72x6
Bef-93
840
40 Champernowne's constant
16ms
69x7
Bef-93
210
41 Pandigital prime
31ms
40x17
Bef-93
7,652,413
42 Coded triangle numbers
406ms
112x1788
Bef-98
162
43 Sub-string divisibility
140ms
68x23
Bef-93
16,695,334,890
44 Pentagon numbers
4min 18s
60x11
Bef-93
5,482,660
45 Triangular, pentagonal, and hexagonal
3.49s
48x6
Bef-93
1,533,776,805
46 Goldbach's other conjecture
13s
200x57
Bef-98
5,777
47 Distinct primes factors
8min 57s
400x518
Bef-98
134,043
48 Self powers
3.73s
37x3
Bef-93
9,110,846,700
49 Prime permutations
124ms
66x8
Bef-93
296,962,999,629
50 Consecutive prime sum
30s
2000x512
Bef-98
997,651
51 Prime digit replacements
1min 53s
78x20
Bef-93
121,313
52 Permuted multiples
2.92s
45x6
Bef-93
142,857
53 Combinatoric selections
125ms
80x7
Bef-93
4,075
54 Poker hands
2.54s
118x1009
Bef-98
376
55 Lychrel numbers
2.22s
56x5
Bef-93
249
56 Powerful digit sum
13s
75x11
Bef-93
972
57 Square root convergents
15s
80x54
Bef-98
153
58 Spiral primes
12s
50x17
Bef-93
26,241
59 XOR decryption
6.30s
273x128
Bef-98
107,359
60 Prime pair sets
33min
3323x3360
Bef-98
26,033
61 Cyclical figurate numbers
14s
80x25
Bef-93
28,684
62 Cubic permutations
6min 3s
505x58
Bef-98
127,035,954,683
63 Powerful digit counts
2.76s
80x10
Bef-93
49
64 Odd period square roots
5.80s
51x9
Bef-93
1,322
65 Convergents of e
124ms
80x14
Bef-93
272
66 Diophantine equation
55s
80x25
Bef-93
661
67 Maximum path sum II
266ms
299x101
Bef-98
7,273
68 Magic 5-gon ring
78ms
39x25
Bef-93
6,531,031,914,842,725
69 Totient maximum
16ms
80x10
Bef-93
510,510
70 Totient permutation
3.71s
150x47
Bef-98
8,319,823
71 Ordered fractions
11s
73x8
Bef-93
428,570
72 Counting fractions
50s
486x1047
Bef-98
303,963,552,391
73 Counting fractions in a range
3min 22s
2000x12010
Bef-98
7,295,372
74 Digit factorial chains
49s
1224x833
Bef-98
402
75 Singular integer right triangles
39s
1000x1515
Bef-98
161,667
76 Counting summations
32ms
104x108
Bef-98
190,569,291
77 Prime summations
47ms
101x39
Bef-98
71
78 Coin partitions
2min 50s
251x256
Bef-98
55,374
79 Passcode derivation
0ms
56x21
Bef-93
73,162,890
80 Square root digital expansion
1min 56s
69x18
Bef-93
40,886
81 Path sum: two ways
234ms
500x180
Bef-98
427,337
82 Path sum: three ways
2.11s
500x180
Bef-98
260,324
83 Path sum: four ways
1.75s
500x180
Bef-98
425,185
84 Monopoly odds
19s
77x20
Bef-93
101,524
85 Counting rectangles
109ms
35x8
Bef-93
2,772
86 Cuboid route
1min 31s
66x10
Bef-93
1,818
87 Prime power triples
27s
1000x1018
Bef-98
1,097,343
88 Product-sum numbers
23s
1024x50
Bef-98
7,587,457
89 Roman numerals
78ms
73x1009
Bef-98
743
90 Cube digit pairs
54s
80x45
Bef-98
1,217
91 Right triangles with integer coordinates
343ms
36x5
Bef-93
14,234
92 Square digit chains
6min 19s
80x16
Bef-93
8,581,146
93 Arithmetic expressions
42s
111x211
Bef-98
1,258
94 Almost equilateral triangles
0ms
40x5
Bef-93
518,408,346
95 Amicable chains
4min 2s
2017x1035
Bef-98
14,316
96 Su Doku
1min 30s
218x50
Bef-98
24,702
97 Large non-Mersenne prime
21s
13x5
Bef-93
8,739,992,577
98 Anagramic squares
22s
258x199
Bef-98
18,769
99 Largest exponential
1.11s
63x1000
Bef-98
709
100 Arranged probability
0ms
56x3
Bef-93
756,872,327,473