login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A157571 Half the number of length n integer sequences with sum zero and sum of squares 3042. 1
1, 9, 270, 10990, 622725, 43526469, 2629049500, 142957923228, 7300452572415, 342254197570615, 14695487432860410, 589524950365892190, 22721530823371062501, 851515705898338365990, 31013728074479042288280 (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,0,3042)/2.

CROSSREFS

Sequence in context: A168600 A088672 A300169 * A202689 A218693 A258302

Adjacent sequences:  A157568 A157569 A157570 * A157572 A157573 A157574

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 | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 27 09:08 EDT 2020. Contains 338035 sequences. (Running on oeis4.)