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A157552 Half the number of length n integer sequences with sum zero and sum of squares 800. 1
1, 3, 42, 3410, 143445, 4303761, 117586819, 2875510809, 67804504560, 1524258428187, 33435072500775, 715914503534022, 14685555146992730, 286576099225123995, 5347457520977926782, 96148425385860533358 (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,0,800)/2.

CROSSREFS

Sequence in context: A083402 A145984 A213956 * A058808 A155210 A157572

Adjacent sequences:  A157549 A157550 A157551 * A157553 A157554 A157555

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 02 2009

STATUS

approved

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Last modified February 29 05:25 EST 2020. Contains 332353 sequences. (Running on oeis4.)