This program finds the largest bi-truncatable prime:
$ bitruncatable-primes
3711663323341112731993391937313 (31 digits)
72471166332334111273199339193731311 (35 digits)
88671166332334111273199339193731911 (35 digits)
3193381663323341112731993391937791971 (37 digits)
…
7228828176786792552781668926755667258635743361825711373791931117197999133917737137399993737111177 (97 digits)
# Statistics (length, count):
# 1 4
# 3 59
# 5 494
# 7 2833
# 9 12718
# 11 46807
# 13 141900
# 15 377342
# 17 877916
# 19 1783865
# 21 3332745
# 23 5693162
# 25 8840023
# 27 12827559
# 29 17284717
# 31 21660200
# 33 25647604
# 35 28554805
# 37 29673844
# 39 29660754
# 41 28530978
# 43 25687627
# 45 22285448
# 47 18647299
# 49 14610917
# 51 11147972
# 53 8208662
# 55 5697725
# 57 3911948
# 59 2609130
# 61 1639381
# 63 1015824
# 65 604159
# 67 345710
# 69 196217
# 71 107676
# 73 56658
# 75 29829
# 77 15099
# 79 7129
# 81 3404
# 83 1503
# 85 688
# 87 312
# 89 132
# 91 46
# 93 24
# 95 13
# 97 3- C++11 compiler (with OpenOMP 3.1 support)
- GMP