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A157537 Half the number of length n integer sequences with sum zero and sum of squares 50. 1
1, 3, 42, 310, 1965, 12621, 86828, 614664, 4137255, 24696507, 135776850, 704076594, 3499379975, 16814719845, 78438871176, 355384933088, 1560604589541, 6638708644299, 27407266803082, 110092581701214, 431253742334877 (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,0,50)/2.

CROSSREFS

Sequence in context: A229071 A220857 A340613 * A322893 A114943 A119577

Adjacent sequences:  A157534 A157535 A157536 * A157538 A157539 A157540

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 02 2009

STATUS

approved

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Last modified August 19 16:22 EDT 2022. Contains 356229 sequences. (Running on oeis4.)