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- #!/usr/bin/ruby
- # Primes in A323426.
- # https://oeis.org/A331265
- # Known terms:
- # 211, 322111, 4332221111
- # Next term, if it exists, is greater than A323426(k), with k = 309, which has more than 10^5 number of digits.
- func a(n) {
- var t = ""
- for k in (1..n) {
- t += ("#{n - k + 1}" * k)
- }
- t.to_i
- }
- for k in (310..1e5) {
- var t = a(k)
- say "Testing: #{k} -- len: #{t.len}"
- if (t.is_prob_prime) {
- say "Prime found for k = #{k}"
- if (k > 4) {
- die "New term found: #{k}"
- }
- }
- }
- __END__
- ...
- Testing: 301 -- len: 108732
- Testing: 302 -- len: 109530
- Testing: 303 -- len: 110331
- Testing: 304 -- len: 111135
- Testing: 305 -- len: 111942
- Testing: 306 -- len: 112752
- Testing: 307 -- len: 113565
- Testing: 308 -- len: 114381
- Testing: 309 -- len: 115200
- Testing: 310 -- len: 116022
- ^C
- 3450.34s user 5.55s system 93% cpu 1:01:23.04 total
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