OFFSET
1,2
COMMENTS
a(n) = A290580(n+2,1) for n>=1.
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 1..75
FORMULA
a(n) ~ c * n^(n+2), where c = (exp(5) - 4*exp(3) - exp(1))/16 = 4.0845455988354304513775733719295... - Vaclav Kotesovec, Aug 21 2017
PROG
(PARI) /* As column 1 of triangle A290580 */
{ A290580(n, k) = my(W=1, E=1, S=x, C=1, D=1); for(i=0, n,
S = intformal(C*D +x*O(x^n)) ;
C = 1 - intformal(S*D) ; D = 1 - m*intformal(S*C) ;
E = subst( (1 + S)/C, m, 1-m) ) ;
for(i=0, n, W = subst(E, x, x*W));
n!*polcoeff(polcoeff(W, n, x), k, m) }
for(n=1, 25, print1( A290580(n+2, 1), ", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Aug 07 2017
STATUS
approved