A157707 The z^2 coefficients of the polynomials in the GF3 denominators of A156927 divided by 2

16, 205, 1165, 4415, 13055, 32606, 72030, 144930, 270930, 477235, 800371, 1288105, 2001545, 3017420, 4430540, 6356436, 8934180, 12329385, 16737385, 22386595, 29542051, 38509130, 49637450, 63324950

Offset

1,1

Comments

See A157704 for background information.

Links

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

Formula

a(n) = 7*a(n-1)-21*a(n-2)+35*a(n-3)-35*a(n-4)+21*a(n-5)-7*a(n-6)+a(n-7)

a(n) = 1/4*n^6+7/4*n^5+37/8*n^4+34/6*n^3+25/8*n^2+7/12*n

G.f.: (16 + 93*z + 66*z^2 + 5*z^3)/(1-z)^7

Maple

nmax:=24; for n from 0 to nmax do fz(n):=product((1-(k+1)*z)^(1+3*k), k=0..n); c(n):= coeff(fz(n), z, 2)/2; end do: a:=n-> c(n): seq(a(n), n=1..nmax);

Crossrefs

Cf. A156927, A157704.

Sequence in context: A221825 A238282 A161729 * A016217 A055758 A046088

Adjacent sequences: A157704 A157705 A157706 * A157708 A157709 A157710

Keyword

easy,nonn

Author

Johannes W. Meijer, Mar 07 2009

Status

approved