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A157053 Number of integer sequences of length n+1 with sum zero and sum of absolute values 8. 1
2, 24, 162, 780, 2970, 9492, 26474, 66222, 151560, 322190, 643632, 1219374, 2206932, 3838590, 6447660, 10501172, 16639974, 25727292, 38906870, 57671880, 83945862, 120177024, 169447302, 235597650, 323371100, 438575202, 588265524, 780951962, 1026829680 (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,4); 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+3*x+9*x^2+9*x^3+9*x^4+3*x^5+x^6)/(1-x)^9. - Colin Barker, Mar 17 2012

a(n) = n(n+1)(n^2+n+6)(n^4+2n^3+23n^2+22n+24)/576. - Bruno Berselli, Mar 17 2012

CROSSREFS

Cf. A103881, A156554.

Sequence in context: A241623 A288443 A108476 * A279853 A052411 A073066

Adjacent sequences:  A157050 A157051 A157052 * A157054 A157055 A157056

KEYWORD

nonn,easy

AUTHOR

R. H. Hardin Feb 22 2009

STATUS

approved

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Last modified July 10 12:34 EDT 2020. Contains 335576 sequences. (Running on oeis4.)