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 A135901 #2 Mar 30 2012 18:37:08
%S A135901 1,2,4,7,12,18,26,36,47,60,75,92,111,132,154,178,204,232,262,294,328,
%T A135901 364,402,442,484,527,572,619,668,719,772,827,884,943,1004,1067,1132,
%U A135901 1199,1268,1339,1412,1487,1564,1643,1724,1807,1892,1978,2066,2156,2248
%N A135901 Number of terms in row n of irregular triangle A135879 for n>=0.
%F A135901 G.f.: A(x) = (1+x^2)/(1-x)^3 - [Sum_{n>=1} x^b(n)]/(1-x)^2, where b(n) = (2^(n+1) + 6*n + 3 + (-1)^n)/12.
%e A135901 A(x) = (1+x^2)/(1-x)^3 - [x+x^2+x^3+x^5+x^8+x^14+x^25+x^47+x^90+x^176+...]/(1-x)^2.
%o A135901 (PARI) {a(n)=polcoeff((1+x^2)/(1-x+x*O(x^n))^3 - sum(k=1,#binary(n)+2,x^((2^(k+1)+6*k+3+(-1)^k)/12))/(1-x +x*O(x^n) )^2,n)}
%Y A135901 Cf. A135879.
%K A135901 nonn
%O A135901 0,2
%A A135901 _Paul D. Hanna_, Dec 16 2007