This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A273601 #10 Nov 11 2024 14:14:40 %S A273601 5,31,271,929,2789,4153 %N A273601 Numbers k such that (11^k - 9^k)/2 is prime. %C A273601 All terms are prime. %C A273601 The corresponding primes: 51001, 95780952266636767336259095696501, ... %C A273601 a(7) > 50000. - _Michael S. Branicky_, Nov 11 2024 %t A273601 Select[Range[1, 10000], PrimeQ[(11^# - 9^#)/2] &] %o A273601 (PARI) for(n=1, 10000, if(isprime((11^n - 9^n)/2), print1(n, ", "))) %Y A273601 Cf. A005808, A210506, A128027, A216181, A128347, A273598, A273599, A273600, A062577. %K A273601 nonn,more,hard %O A273601 1,1 %A A273601 _Tim Johannes Ohrtmann_, May 26 2016