A157601 Half the number of length n integer sequences with sum zero and sum of squares 9522.

1, 3, 450, 35490, 3461325, 429808743, 45598808332, 4382814679428, 396120762708465, 32858020705796385, 2495992345644237990, 177151945927883401410, 12079996873394323662971, 800952129262668313107765

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,0,9522)/2.

Crossrefs

Sequence in context: A092052 A139999 A140870 * A094454 A261004 A157587

Adjacent sequences: A157598 A157599 A157600 * A157602 A157603 A157604

Keyword

nonn

Author

R. H. Hardin Mar 02 2009

Status

approved