A157592 Half the number of length n integer sequences with sum zero and sum of squares 7200.

1, 3, 126, 23870, 2725455, 314174553, 29749465207, 2182715679324, 150186806030400, 10125676123572801, 666260841650613825, 42448715774998807794, 2597948199840416316530, 152089661374768398565935

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,0,7200)/2.

Crossrefs

Sequence in context: A157562 A324152 A274314 * A213988 A159319 A086154

Adjacent sequences: A157589 A157590 A157591 * A157593 A157594 A157595

Keyword

nonn

Author

R. H. Hardin Mar 02 2009

Status

approved