|
Search: id:A157566
|
|
|
| A157566 |
|
Half the number of length n integer sequences with sum zero and sum of squares 2312. |
|
+0
1
|
|
| 1, 3, 102, 8190, 665685, 36705753, 1679350127, 68733531189, 2760184991340, 106183264044550, 3966764429800029, 144378604643078598, 5032695166253713140, 166954292511159130110, 5296343179095984782250, 161894623559389026065130
(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,0,2312)/2.
|
|
CROSSREFS
|
Sequence in context: A130733 A037062 A157549 this_sequence A157600 A139908 A128070
Adjacent sequences: A157563 A157564 A157565 this_sequence A157567 A157568 A157569
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Ron Hardin (rhhardin(AT)att.net) Mar 02 2009
|
|
|
Search completed in 0.002 seconds
|
