A157055 Number of integer sequences of length n+1 with sum zero and sum of absolute values 12.

2, 36, 362, 2570, 14240, 65226, 256508, 889716, 2777370, 7925720, 20934474, 51697802, 120353324, 265953170, 561075720, 1135620536, 2214405618, 4175000796, 7634582090, 13577591370, 23539760552, 39868752506, 66087441092, 107392877100, 171332460650, 268708978512

Offset

1,1

Links

T. D. Noe, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (13,-78,286,-715,1287,-1716,1716,-1287,715,-286,78,-13,1).

Formula

a(n) = T(n,6); T(n,k) = Sum_(i=1..n} binomial(n+1,i)*binomial(k-1,i-1)*binomial(n-i+k,k).

G.f.: 2*x*(1 +5*x +25*x^2 +50*x^3 +100*x^4 +100*x^5 +100*x^6 +50*x^7 +25*x^8 +5*x^9 +x^10)/(1-x)^13. - Colin Barker, Jan 25 2013

From G. C. Greubel, Jan 24 2022: (Start)

a(n) = n*(n+1)*(n^10 +5*n^9 +120*n^8 +450*n^7 +4173*n^6 +10965*n^5 +48530*n^4 +79300*n^3 +163176*n^2 +125280*n +86400)/518400.

E.g.f.: (x/518400)*(1036800 +8294400*x +22464000*x^2 +28728000*x^3 +20131200*x^4 +8369280*x^5 +2154240*x^6 +349200*x^7 +35400*x^8 +2160*x^9 +72*x^10 +x^11)*exp(x). (End)

Mathematica

Table[n*(n+1)*(n^10 +5*n^9 +120*n^8 +450*n^7 +4173*n^6 +10965*n^5 +48530*n^4 +79300*n^3 +163176*n^2 +125280*n +86400)/518400, {n, 50}] (* G. C. Greubel, Jan 24 2022 *)

Prog

(Sage) [n*(n+1)*(n^10 +5*n^9 +120*n^8 +450*n^7 +4173*n^6 +10965*n^5 +48530*n^4 +79300*n^3 +163176*n^2 +125280*n +86400)/518400 for n in (1..50)] # G. C. Greubel, Jan 24 2022

Crossrefs

Cf. A103881, A156554.

Sequence in context: A126735 A229679 A119582 * A057407 A286266 A193127

Adjacent sequences: A157052 A157053 A157054 * A157056 A157057 A157058

Keyword

nonn,easy

Author

R. H. Hardin, Feb 22 2009

Status

approved