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 A228647 #6 Nov 15 2013 00:53:39
%S A228647 1,5,31,453,14131,946781,136250983,42115660581,27961563559891,
%T A228647 39874307297033165,122134599693975367423,803522677430288749340325,
%U A228647 11354589189995520431547851761,344634362031276605039944979868611,22467750416780812361715214948922598721,3146114090698891414621617889648190060326821
%N A228647 a(n) = A001609(n^2) for n>=1, where g.f. of A001609 is x*(1+3*x^2)/(1-x-x^3).
%C A228647 A001609 forms the logarithmic derivative of Narayana's cows sequence A000930.
%F A228647 Equals the logarithmic derivative of A228648.
%e A228647 L.g.f.: L(x) = x + 5*x^2/2 + 31*x^3/3 + 453*x^4/4 + 14131*x^5/5 +...
%e A228647 where
%e A228647 exp(L(x)) = 1 + x + 3*x^2 + 13*x^3 + 128*x^4 + 2974*x^5 + 161048*x^6 + 19632276*x^7 +...+ A228648(n)*x^n +...
%o A228647 (PARI) {A001609(n)=n*polcoeff(-log(1-x-x^3 +x*O(x^n)), n)}
%o A228647 {a(n)=A001609(n^2)}
%o A228647 for(n=1,20,print1(a(n),", "))
%Y A228647 Cf. A218439, A228648, A001609, A000930, A231620.
%K A228647 nonn
%O A228647 1,2
%A A228647 _Paul D. Hanna_, Aug 28 2013