OFFSET
1,2
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.
KEYWORD
easy,nonn
AUTHOR
Johannes W. Meijer, Jun 27 2009
STATUS
approved