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A157554 Half the number of length n integer sequences with sum zero and sum of squares 968. 1

%I #4 Mar 31 2012 12:35:25

%S 1,3,66,3990,178335,6510483,190667659,5047394427,131071431060,

%T 3262733109790,78872812374741,1857536871457917,41896936373100900,

%U 899337065318075790,18460566561637223550,365127965985604164628

%N Half the number of length n integer sequences with sum zero and sum of squares 968.

%H R. H. Hardin, <a href="/A157554/b157554.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,0,968)/2.

%K nonn

%O 2,2

%A _R. H. Hardin_ Mar 02 2009

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Last modified June 20 02:43 EDT 2024. Contains 373512 sequences. (Running on oeis4.)