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A354655
Column 2 of triangle A354650: a(n) = A354650(n,2), for n >= 1.
6
3, 27, 147, 630, 2295, 7476, 22302, 62100, 163260, 409080, 983367, 2280306, 5122026, 11184075, 23806575, 49521456, 100872135, 201558231, 395675475, 764130780, 1453424259, 2725614243, 5044092372, 9219499800, 16655554125, 29759775435, 52623867051
OFFSET
1,1
LINKS
FORMULA
a(n) = (-1)^(n+1) * A354649(n,2), for n >= 1.
a(n) = A354650(n,2), for n >= 1.
PROG
(PARI) {A354650(n, k) = my(A=[1+y]); for(i=1, n, A = concat(A, 0);
A[#A] = polcoeff(y + sum(m=0, sqrtint(2*#A+9), (-1)^m * x^(m*(m-1)/2) * (1 - x^(2*m+1)) * Ser(A)^(m*(m+1)/2) ), #A-1) );
polcoeff(A[n+1], k, y)}
for(n=1, 30, print1(A354650(n, 2), ", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jun 02 2022
STATUS
approved