|
| |
|
|
A157539
|
|
Half the number of length n integer sequences with sum zero and sum of squares 98.
|
|
1
| |
|
|
1, 9, 54, 430, 5265, 51471, 471996, 4601556, 43269345, 363940555, 2806131702, 20371562718, 141703205917, 953199973950, 6225689789880, 39490548010664, 242779946083425, 1445870078850825, 8356848826556090, 46996171775421630
(list; graph; refs; listen; history; 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,0,98)/2.
|
|
|
CROSSREFS
| Sequence in context: A037599 A037704 A093847 * A205814 A157546 A157560
Adjacent sequences: A157536 A157537 A157538 * A157540 A157541 A157542
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| R. H. Hardin (rhhardin(AT)att.net) Mar 02 2009
|
| |
|
|
