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 A244624 #5 Jul 03 2014 16:18:28
%S A244624 1,2,4,9,14,34,61,120,215,690,1144,2584,5626,13709,31275,63461,145767,
%T A244624 340332,649190,1703684,4218462,10675070,22892978
%N A244624 Consider the number of lines in the Pratt certificate for the n-th prime (A037202). This sequence shows where 2n first occurs.
%C A244624 See comment section of A037202.
%C A244624 a(n) ~ 2*a(n-1).
%F A244624 Also PrimePi( A037231 ).
%t A244624 a[1] = 1; a[n_] := a[n] = 1 + Plus @@ (a@ PrimePi@# & /@ First /@ FactorInteger[ Prime@ n - 1]); k = 1; t = Table[0, {1000}]; While[k < 1000000000000001, If[a@ k < 1001 && t[[a[k]/2]] == 0, t[[a[k]/2]] = k; Print[{a@k, k}]]; k++]; t
%Y A244624 Cf. A037202, A037231.
%K A244624 nonn,more
%O A244624 0,2
%A A244624 _Joerg Arndt_ and _Robert G. Wilson v_, Jul 02 2014