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A157545 Half the number of length n integer sequences with sum zero and sum of squares 338. 1
1, 9, 90, 1570, 32775, 596253, 10391500, 188323164, 3295910835, 51520770235, 737464758030, 9942564439314, 128439149539155, 1604475021960825, 19461485770566600, 229260099669952384, 2617537416673754961 (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,0,338)/2.

CROSSREFS

Sequence in context: A294813 A218118 A160569 * A274953 A157558 A157584

Adjacent sequences:  A157542 A157543 A157544 * A157546 A157547 A157548

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 02 2009

STATUS

approved

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Last modified July 4 17:52 EDT 2022. Contains 355083 sequences. (Running on oeis4.)