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A157707 The z^2 coefficients of the polynomials in the GF3 denominators of A156927 divided by 2 1

%I #2 Mar 30 2012 18:59:44

%S 16,205,1165,4415,13055,32606,72030,144930,270930,477235,800371,

%T 1288105,2001545,3017420,4430540,6356436,8934180,12329385,16737385,

%U 22386595,29542051,38509130,49637450,63324950

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

%C See A157704 for background information.

%F 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)

%F 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

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

%p 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);

%Y Cf. A156927, A157704.

%K easy,nonn

%O 1,1

%A _Johannes W. Meijer_, Mar 07 2009

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Last modified March 29 05:48 EDT 2024. Contains 371265 sequences. (Running on oeis4.)