cp's OEIS Frontend

A290581 Column 1 of triangle A290580.

%I A290581 #8 Aug 21 2017 17:29:10
%S A290581 1,20,364,7028,148752,3471192,89097664,2503362488,76575071488,
%T A290581 2536513162508,90532686154752,3465845396598540,141726054915248128,
%U A290581 6167370619705004144,284635248765764878336,13889365886508877963184,714612366728939248091136,38667882915659893417754820,2195406208657284278474506240,130509259754593318496376665060,8107405596523654695095077175296,525358015896796804145274761270600
%N A290581 Column 1 of triangle A290580.
%C A290581 a(n) = A290580(n+2,1) for n>=1.
%H A290581 Vaclav Kotesovec, <a href="/A290581/b290581.txt">Table of n, a(n) for n = 1..75</a>
%F A290581 a(n) ~ c * n^(n+2), where c = (exp(5) - 4*exp(3) - exp(1))/16 = 4.0845455988354304513775733719295... - _Vaclav Kotesovec_, Aug 21 2017
%o A290581 (PARI) /* As column 1 of triangle A290580 */
%o A290581 { A290580(n,k) = my(W=1,E=1, S=x,C=1,D=1); for(i=0,n,
%o A290581 S = intformal(C*D +x*O(x^n)) ;
%o A290581 C = 1 - intformal(S*D) ; D = 1 - m*intformal(S*C) ;
%o A290581 E = subst( (1 + S)/C,m,1-m) ) ;
%o A290581 for(i=0,n, W = subst(E,x,x*W));
%o A290581 n!*polcoeff(polcoeff(W, n,x), k,m) }
%o A290581 for(n=1,25, print1( A290580(n+2,1), ", "))
%Y A290581 Cf. A290580, A291214.
%K A290581 nonn
%O A290581 1,2
%A A290581 _Paul D. Hanna_, Aug 07 2017