

A157551


Half the number of length n integer sequences with sum zero and sum of squares 722.


1



1, 9, 114, 3810, 103185, 2729181, 69340908, 1835068068, 46949243445, 1072699180795, 22440539853666, 442180822802082, 8348531623530553, 152424934237053765, 2702148696449820840, 46523455154624265192
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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=(ts)/n, tt=ss+2*q*s+n*q^2; count(n,t,tt)=sum[i^2<=tt]{ count(n1,ti,tti^2) }. a(n)=count(n,0,722)/2.


CROSSREFS

Sequence in context: A165224 A243676 A012116 * A157570 A223499 A157233
Adjacent sequences: A157548 A157549 A157550 * A157552 A157553 A157554


KEYWORD

nonn


AUTHOR

R. H. Hardin Mar 02 2009


STATUS

approved



