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

Author

Johannes W. Meijer, Mar 07 2009

Keywords

• easy
• nonn

Comments

See A157704 for background information.

Crossrefs

Cf. A156927, A157704.

Programs

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);

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