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A157599 Half the number of length n integer sequences with sum zero and sum of squares 8978. 1
1, 9, 402, 44230, 4512465, 423267831, 37803628716, 3527887213476, 318332583745245, 25647872392849575, 1892012326768856754, 131465592083214083058, 8752726227773492626389, 563521423775802944905950 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

LINKS

R. H. Hardin, Table of n, a(n) for n=2..50

FORMULA

[cache enabling] count(n,s,ss)->count(n,t,tt) where t=s mod n, q=(t-s)/n, tt=ss+2*q*s+n*q^2; count(n,t,tt)=sum[i^2<=tt]{ count(n-1,t-i,tt-i^2) }. a(n)=count(n,0,8978)/2.

CROSSREFS

Sequence in context: A012078 A332139 A266924 * A063876 A063156 A058850

Adjacent sequences:  A157596 A157597 A157598 * A157600 A157601 A157602

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 02 2009

STATUS

approved

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Last modified November 30 06:28 EST 2021. Contains 349419 sequences. (Running on oeis4.)