A126267 - OEIS

%I #3 Mar 30 2012 18:37:02

%S 1,6,24,140,1320,12432,121072,1420848,19012320,267512300,4002574224,

%T 64842612276,1121345413552,20409576486600,390729145716480,

%U 7869294632279648,166020221631955680,3654120873937484628

%N A diagonal of triangle A126265: a(n) = A126265(n+2,n).

%C a(n) is divisible by (n+1)*(n+2)/2. Rows of triangle A126265 lists coefficients of q in e.g.f. that satisfies: W(x,q) = exp( q*x*W(q*x,q) ).

%o (PARI) {a(n)=local(W=x);for(i=1,n+2,W=x*exp(subst(W,x,q*x+x*O(x^(n+2))))); if(n<0,0,Vec(Vec(W)[n+3]*(n+2)!+q*O(q^((n+2)*(n+3)/2)))[n+1])}

%Y Cf. A126265, A126266.

%K nonn

%O 0,2

%A _Paul D. Hanna_, Dec 22 2006