|
Search: id:A157543
|
|
|
| A157543 |
|
Half the number of length n integer sequences with sum zero and sum of squares 242. |
|
+0
1
|
|
| 1, 3, 66, 1330, 19815, 310023, 4512844, 69146820, 1023450345, 13538157655, 163977086526, 1870633964706, 20447484311345, 216134818489905, 2218284360150120, 22111545640638832, 213615563307370209
(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,0,242)/2.
|
|
CROSSREFS
|
Sequence in context: A091470 A028567 A003359 this_sequence A157984 A157554 A165655
Adjacent sequences: A157540 A157541 A157542 this_sequence A157544 A157545 A157546
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Ron Hardin (rhhardin(AT)att.net) Mar 02 2009
|
|
|
Search completed in 0.002 seconds
|
