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A157595 Half the number of length n integer sequences with sum zero and sum of squares 7938. 1
1, 9, 486, 26230, 2658825, 303936255, 29022562044, 2546840675268, 209628417451815, 15863225333113455, 1100628488842991790, 71323826984704710078, 4440654868991991482287, 268844012960749492143465 (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,0,7938)/2.

CROSSREFS

Sequence in context: A293951 A267236 A306820 * A042415 A277360 A332149

Adjacent sequences:  A157592 A157593 A157594 * A157596 A157597 A157598

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 02 2009

STATUS

approved

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Last modified July 2 03:47 EDT 2022. Contains 354985 sequences. (Running on oeis4.)