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A157584 Half the number of length n integer sequences with sum zero and sum of squares 5408. 1
1, 9, 90, 17270, 2392575, 203322273, 14072688875, 881578169937, 54028224275760, 3177868465756435, 181594395820598805, 10109617693345774539, 538976083520642296074, 27345902242485061861185, 1326768997661185039512750 (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,0,5408)/2.

CROSSREFS

Sequence in context: A157545 A274953 A157558 * A077334 A020243 A239867

Adjacent sequences:  A157581 A157582 A157583 * A157585 A157586 A157587

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 02 2009

STATUS

approved

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Last modified July 2 21:48 EDT 2022. Contains 355029 sequences. (Running on oeis4.)