A157708 The z^2 coefficients of the polynomials in the GF4 denominators of A156933.

18, 254, 1571, 6335, 19615, 50743, 115234, 237066, 451320, 807180, 1371293, 2231489, 3500861, 5322205, 7872820, 11369668, 16074894, 22301706, 30420615, 40866035, 54143243, 70835699, 91612726

Offset: 1

Author

Johannes W. Meijer, Mar 07 2009

Keywords

• easy
• nonn

Comments

See A157705 for background information.

Crossrefs

Cf. A156933, A157705

Programs

Maple

nmax:=23; for n from 0 to nmax do fz(n):=product((1-(2*n+1-2*k)*z)^(3*k+1), k=0..n); c(n):= coeff(fz(n),z,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) = 1/2*n^6+5/2*n^5+41/8*n^4+67/12*n^3+27/8*n^2+11/12*n

G.f.: (18 + 128*z + 171*z^2 + 42*z^3 + z^4)/(1-z)^7