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A157573 Half the number of length n integer sequences with sum zero and sum of squares 3362. 1
1, 3, 246, 17230, 1034445, 59305701, 3243926588, 185256960120, 10229264210745, 504340200498475, 22766981281651398, 968060807776968126, 39440547846380819957, 1553885734839506217555, 59443252831855326838200 (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,0,3362)/2.

CROSSREFS

Sequence in context: A092799 A229690 A140163 * A082717 A157777 A318065

Adjacent sequences:  A157570 A157571 A157572 * A157574 A157575 A157576

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 02 2009

STATUS

approved

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Last modified October 20 02:33 EDT 2020. Contains 337897 sequences. (Running on oeis4.)