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