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 A377511 #6 Nov 04 2024 22:30:14
%S A377511 3,2,4,1,2,1,3,1,4,1,1,1,2,1,2,3,1,1,1,2,1,1,3,1,1,1,1,1,1,2,1,2,3,1,
%T A377511 1,1,1,1,1,2,1,1,2,1,3,1,1,1,3,1,1,1,1,2,3,1,1,1,1,2,1,5,1,1,1,3,1,1,
%U A377511 3,1,1,1,1,1,1,3,1,1,2,1,1,1,1,1,1,1
%N A377511 a(n) = number of iterations of x -> 2 x + 7 to reach a nonprime, starting with prime(n).
%C A377511 See A377120 for a guide to related sequences.
%e A377511 prime(3) = 5 -> 17 -> 41 -> 89 -> 185 = 5*37, so a(3) = 4.
%t A377511 Table[p = Prime[n]; c = 1; While[p = 2*p + 7; PrimeQ[p], c++]; c, {n, 200}]
%Y A377511 Cf. A377120, A377510, A377512, A377513, A377514.
%K A377511 nonn
%O A377511 1,1
%A A377511 _Clark Kimberling_, Oct 31 2024