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 A278801 #9 Dec 07 2016 11:05:40
%S A278801 0,0,1,2,1,3,1,3,2,2,1,5,1,3,2,3,2,4,1,5,2,3,1,5,2,3,3,4,1,4,1,7,3,2,
%T A278801 1,5,2,4,3,4,1,6,2,6,2,3,2,5,1,5,3,5,2,5,2,4,3,3,1,9,1,6,3,3,2,3,3,7,
%U A278801 3,4,1,7,1,6,2,5,3,5,1,7,4,3,1,6,1,6,6,4,1,5,1,7,3,4,3,5,2,7,2,6,1
%N A278801 G.f.: Sum_{k>0} x^prime(k)/(1-x^k).
%C A278801 New maxima occur at 2,3,5,11,31,59,211,331,619,1759,2341,3049,4343,12373,15431,18691,31667,66643,67651,...
%C A278801 4343 and 15431 are the only composites in the terms displayed above.
%C A278801 If we define a new maximum as greater than or equal to the previous maximum we get
%C A278801 1,2,3,5,7,11,19,23,31,59,131,163,167,197,211,331,467,521,547,...
%C A278801 This is very dense with primes and contains the previous list as a subset.
%F A278801 G.f.: Sum_{k>0} x^prime(k)/(1-x^k).
%t A278801 NN=200;MM=PrimePi[NN]+1; Table[Boole[n>2]+Sum[Boole[(n>Prime[k])&&(Mod[n-Prime[k]+k-1,k] == 0)], {k, 2, MM}], {n, 1, NN}]
%K A278801 nonn
%O A278801 0,4
%A A278801 _Benedict W. J. Irwin_, Nov 28 2016