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 A102170 #13 Jun 05 2025 00:43:06 %S A102170 2801,16148168401, %T A102170 85053461164796801949539541639542805770666392330682673302530819774105141531698707146930307290253537320447270457 %N A102170 Primes of the form (7^k-1)/6. %C A102170 The next term, for k=149, has 126 digits. %H A102170 Amiram Eldar, <a href="/A102170/b102170.txt">Table of n, a(n) for n = 1..4</a> %F A102170 a(n) = A023000(A004063(n)). - _Amiram Eldar_, Jun 04 2025 %t A102170 Select[(7^Range[200]-1)/6, PrimeQ] %Y A102170 Cf. A023000 ((7^n-1)/6), A004063 (k such that (7^k-1)/6 is prime). %K A102170 nonn,hard %O A102170 1,1 %A A102170 _Roger L. Bagula_, Mar 15 2005