|
Search: id:A157577
|
|
|
| A157577 |
|
Half the number of length n integer sequences with sum zero and sum of squares 4050. |
|
+0
1
|
|
| 1, 3, 378, 18910, 992325, 74527005, 5338966892, 339980231676, 20037272191665, 1077068920503015, 53256851208061050, 2465137614876120834, 109671118311748056245, 4742369931941953806600, 199288535032516918383432
(list; graph; listen)
|
|
|
OFFSET
|
2,2
|
|
|
LINKS
|
Ron 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,0,4050)/2.
|
|
CROSSREFS
|
Sequence in context: A110717 A068988 A136025 this_sequence A062604 A160192 A120061
Adjacent sequences: A157574 A157575 A157576 this_sequence A157578 A157579 A157580
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Ron Hardin (rhhardin(AT)att.net) Mar 02 2009
|
|
|
Search completed in 0.002 seconds
|
