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A157578 Half the number of length n integer sequences with sum zero and sum of squares 4232. 1
1, 3, 150, 15210, 1639575, 123643611, 7614820759, 421492526271, 22902703731540, 1192049263269315, 60248523072916695, 2966823784716819963, 139916416171825355244, 6279781745619795030660, 269526833541639073889370 (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,0,4232)/2.

CROSSREFS

Sequence in context: A118840 A111816 A157555 * A137802 A100203 A287319

Adjacent sequences:  A157575 A157576 A157577 * A157579 A157580 A157581

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 02 2009

STATUS

approved

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Last modified December 6 13:45 EST 2021. Contains 349563 sequences. (Running on oeis4.)