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A157052 Number of integer sequences of length n+1 with sum zero and sum of absolute values 6. 1
2, 18, 92, 340, 1010, 2562, 5768, 11832, 22530, 40370, 68772, 112268, 176722, 269570, 400080, 579632, 822018, 1143762, 1564460, 2107140, 2798642, 3670018, 4756952, 6100200, 7746050, 9746802, 12161268, 15055292, 18502290, 22583810, 27390112, 33020768, 39585282 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

a(n) = T(n,3); 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+2*x+4*x^2+2*x^3+x^4)/(1-x)^7. - Colin Barker, Mar 17 2012

a(n) = n(n+1)(n^4+2n^3+11n^2+10n+12)/36. - Bruno Berselli, Mar 17 2012

MAPLE

A157052:=n->n*(n + 1)*(n^4 + 2*n^3 + 11*n^2 + 10*n + 12)/36; seq(A157052(n), n=1..50); # Wesley Ivan Hurt, Feb 03 2014

MATHEMATICA

Table[n (n + 1) (n^4 + 2 n^3 + 11 n^2 + 10 n + 12)/36, {n, 50}] (* Wesley Ivan Hurt, Feb 03 2014 *)

CROSSREFS

Cf. A103881, A156554.

Sequence in context: A201236 A206623 A036800 * A280157 A224616 A052633

Adjacent sequences:  A157049 A157050 A157051 * A157053 A157054 A157055

KEYWORD

nonn,easy

AUTHOR

R. H. Hardin Feb 22 2009

STATUS

approved

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Last modified November 21 11:01 EST 2018. Contains 317447 sequences. (Running on oeis4.)