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 A265484 #23 Jul 10 2025 14:08:56 %S A265484 1,2,3,4,24,63,81,92,165,232,236,591,669,1343,2973,3630,5600,7019, %T A265484 17169,31945,52172 %N A265484 Numbers k such that 36^k - 6^k - 1 is prime. %C A265484 For k = 1, 2, 3, 4, 24 the corresponding primes are 29, 1259, 46439, 1678319, 22452257707354557235348829785471057919. %C A265484 a(22) > 10^5. - _Robert Price_, Jan 06 2020 %e A265484 4 is in the sequence because 36^4 - 6^4 - 1 = 1678319 is prime. %t A265484 Select[Range[1000], PrimeQ[36^# - 6^# - 1] &] %o A265484 (Magma) [n: n in [0..300] | IsPrime(36^n-6^n-1)]; %o A265484 (PARI) for(n=1, 1e3, if(ispseudoprime(36^n - 6^n - 1), print1(n, ", "))) \\ _Altug Alkan_, Dec 12 2015 %Y A265484 Cf. similar sequences listed in A265481. %K A265484 nonn,more %O A265484 1,2 %A A265484 _Vincenzo Librandi_, Dec 12 2015 %E A265484 a(14)-a(18) from _Ray Chandler_, Sep 25 2019 %E A265484 a(18) corrected and a(19)-a(21) added by _Robert Price_, Jan 06 2020