A162012 The sequence of the absolute values of the a(n-2) coefficients of A162011

0, 19, 663, 6501, 36729, 149842, 491274, 1375206, 3413982, 7710813, 16133689, 31690659, 59028879, 105082068, 179893252, 297641916, 477906924, 747198807, 1140797259, 1704931921, 2499346773, 3600290694, 5103978990, 7130572930

Offset

1,2

Links

Table of n, a(n) for n=1..24.

Formula

a(n) = (20*n^8+80*n^7+4*n^6-268*n^5-155*n^4+230*n^3+131*n^2-42*n)/360

Recurrence relation sum((-1)^k*binomial(9,k)*a(n-k), k= 0 .. 9) = 0

GF(z) = z*(19+492*z+1218*z^2+492*z^3+19*z^4)/(1-z)^9

Maple

nmax:=26; for n from 1 to nmax do RR(n) := expand(product((1-(2*k-1)^2*z)^(n-k+1), k=1..n), z) od: T:=1: for n from 1 to nmax do a(T):=coeff(RR(n), z, 2): T:=T+1 od: seq(a(k), k=1..T-1);

Crossrefs

Equals the absolute values of the coefficients that precede the a(n-2) factors of the recurrence relations RR(n) of A162011.

Cf. A006324 [a(n-1)] and A162013 [a(n-3)].

Sequence in context: A217824 A217825 A200849 * A233011 A369373 A280112

Adjacent sequences: A162009 A162010 A162011 * A162013 A162014 A162015

Keyword

easy,nonn

Author

Johannes W. Meijer, Jun 27 2009

Status

approved