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!)
A157574 Half the number of length n integer sequences with sum zero and sum of squares 3528. 1

%I #6 Apr 19 2023 07:50:32

%S 1,9,162,9030,900315,78905043,5045283243,254993728356,12275288985060,

%T 582690164112595,26896406705910159,1199420057394958074,

%U 51363567523493108520,2104956036291257002350,82564460378872392399390

%N Half the number of length n integer sequences with sum zero and sum of squares 3528.

%H R. H. Hardin, <a href="/A157574/b157574.txt">Table of n, a(n) for n=2..50</a>

%F [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,0,3528)/2.

%K nonn

%O 2,2

%A _R. H. Hardin_, Mar 02 2009

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 March 29 04:23 EDT 2024. Contains 371264 sequences. (Running on oeis4.)