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A157706 The z^2 coefficients of the polynomials in the GF1 denominators of A156921. 1
7, 75, 385, 1365, 3850, 9282, 19950, 39270, 72105, 125125, 207207, 329875, 507780, 759220, 1106700, 1577532, 2204475, 3026415, 4089085, 5445825, 7158382, 9297750, 11945050, 15192450, 19144125, 23917257 (list; graph; refs; listen; history; text; internal format)
OFFSET
2,1
COMMENTS
See A157702 for background information.
LINKS
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) = 1/18*n^6+1/6*n^5+1/72*n^4-1/4*n^3-5/72*n^2+1/12*n
G.f.: (7+26*z+7*z^2)/(1-z)^7
MAPLE
nmax:=27; for n from 0 to nmax do fz(n):= product( (1-(2*m-1)*z)^(n+1-m) , m=1..n); c(n):= coeff(fz(n), z, 2); end do: a:=n-> c(n): seq(a(n), n=2..nmax);
CROSSREFS
Sequence in context: A326221 A197091 A174243 * A197763 A202251 A365841
KEYWORD
easy,nonn
AUTHOR
Johannes W. Meijer, Mar 07 2009
STATUS
approved

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Last modified April 18 03:33 EDT 2024. Contains 371767 sequences. (Running on oeis4.)