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%I #4 Mar 30 2012 18:36:46
%S 1,3,18,180,2670,54096,1411228,45421776,1747674405,78485504845,
%T 4037946005808,234494393383614,15187062546935643,1086079262127563445,
%U 85049134680670591560,7241328591814507465712,666283956766298002183275
%N Third diagonal of triangle A108990, in which the g.f. of row n, R_n(x), satisfies: [x^k] R_{n+1}(x) = [x^k] (1 + x*R_n(x))^(n+1) for k=0..n+1.
%C a(n) is divisible by (n+1)*(n+2)/2.
%F a(n) = A108990(n+2, n) for n>=0. a(n) = (n+2)/2*A108995(n) for n>=0.
%o (PARI) {a(n)=local(F=1+x*O(x^n));for(m=1,n+2,F=(1+x*F)^m);polcoeff(F,n)}
%Y Cf. A108990, A108991, A108992, A108993, A108995, A108996.
%K nonn
%O 0,2
%A _Paul D. Hanna_, Jun 15 2005
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