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 A216579 #12 Jan 10 2015 03:10:18 %S A216579 0,0,0,0,0,0,0,0,0,0,1,0,0,1,0,0,0,0,1,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0, %T A216579 1,0,0,0,0,0,1,0,0,1,0,1,0,0,1,0,0,0,0,0,0,1,0,0,1,0,0,0,0,0,1,0,0,0, %U A216579 0,0,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,1,0,2 %N A216579 Number of positive integer solutions to the equation a^2 + 10*b^2 = n. %H A216579 Charles R Greathouse IV, <a href="/A216579/b216579.txt">Table of n, a(n) for n = 1..10000</a> %t A216579 a[ n_] := If[ n < 1, 0, Length@Select[ Range@Sqrt[ n/10], IntegerQ@Sqrt[ n - 10 #] &]]; (* _Michael Somos_, Jan 10 2015 *) %o A216579 (PARI) a(n)=sum(b=1,sqrtint((n-1)\10),issquare(n-10*b^2)) \\ _Charles R Greathouse IV_, Nov 19 2014 %Y A216579 Cf. A020673, A033201. %K A216579 nonn %O A216579 1,91 %A A216579 _V. Raman_, Sep 08 2012