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 A301638 #13 Dec 03 2018 12:47:09
%S A301638 2,11,48828181,298023223876953251,2910383045673370361328301,
%T A301638 258493941422821148397315216271863391739316284656524658203551
%N A301638 Primes of the form 5^k + 5*k + 1.
%C A301638 The next term is too large to include.
%C A301638 The next term has 349 digits. - _Harvey P. Dale_, Dec 03 2018
%F A301638 a(n) = 5^A301635(n) + 5*A301635(n) + 1.
%t A301638 Select[Table[5^n+5n+1,{n,0,550}],PrimeQ] (* _Harvey P. Dale_, Dec 03 2018 *)
%Y A301638 Primes of the form b^k+b*k+1: A163115 (b=2), A180269 (b=3), this sequence (b=5).
%Y A301638 Cf. A301635.
%K A301638 nonn
%O A301638 1,1
%A A301638 _Seiichi Manyama_, Mar 25 2018