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 A126613 #9 Sep 16 2015 04:59:18
%S A126613 1,2,4,7,11,16,22,28,34,40,46,52,58,64,71,79,88,97,107,118,129,140,
%T A126613 151,163,176,189,202,215,228,241,255,269,284,299,314,329,344,359,375,
%U A126613 391,407,423,439,456,473,490,507,524,541,559,577,596,615,634,653,673,694
%N A126613 a(1)=1. a(n) = a(n-1) + (number of terms, from among terms a(1) through a(n-1), which are powers of primes {including 1}).
%e A126613 There are 7 prime powers (1,2,4,7,11,16,64) among the first 14 terms of the sequence. So a(15) = a(14) + 7 = 71.
%t A126613 a = {1}; Do[AppendTo[a, a[[ -1]] + 1 + Length[Select[a, Length[FactorInteger[ # ]] == 1 &]]], {60}]; a (* _Stefan Steinerberger_, Oct 16 2007 *)
%Y A126613 Cf. A131073.
%K A126613 nonn
%O A126613 1,2
%A A126613 _Leroy Quet_, Jun 13 2007
%E A126613 More terms from _Stefan Steinerberger_, Oct 16 2007