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 A218208 #11 Oct 23 2012 13:18:57
%S A218208 1,4,10,26,68,175,461,1225,3349,9266,26516,76334,221763
%N A218208 Number of primes up to 10^n that are of the form (k-1)^2 + k^2.
%F A218208 a(n) = sum(A218207(k), k=1..n)
%t A218208 n = 0; cnt = 0; Table[While[n++; p = 2*n^2 - 2*n + 1; p < 10^e, If[PrimeQ[p], cnt++]]; n--; cnt, {e, 10}] (* _T. D. Noe_, Oct 23 2012 *)
%Y A218208 Cf. A027861, A027862, A218207, A218210, A218212.
%K A218208 nonn,base
%O A218208 1,2
%A A218208 _Martin Renner_, Oct 23 2012