login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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; text; 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 Mar 02 2009

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 6 05:39 EDT 2022. Contains 355108 sequences. (Running on oeis4.)