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A157708 The z^2 coefficients of the polynomials in the GF4 denominators of A156933 1
18, 254, 1571, 6335, 19615, 50743, 115234, 237066, 451320, 807180, 1371293, 2231489, 3500861, 5322205, 7872820, 11369668, 16074894, 22301706, 30420615, 40866035, 54143243, 70835699, 91612726 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

See A157705 for background information.

LINKS

Table of n, a(n) for n=1..23.

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

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);

CROSSREFS

Cf. A156933, A157705

Sequence in context: A255371 A016175 A062141 * A159537 A136660 A255372

Adjacent sequences:  A157705 A157706 A157707 * A157709 A157710 A157711

KEYWORD

easy,nonn

AUTHOR

Johannes W. Meijer, Mar 07 2009

STATUS

approved

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Last modified June 4 17:50 EDT 2020. Contains 334828 sequences. (Running on oeis4.)