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A157556
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Half the number of length n integer sequences with sum zero and sum of squares 1152.
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1
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1, 3, 18, 3010, 166725, 8371713, 307008163, 8869151172, 244109996040, 6625340217595, 174712060895757, 4452494561526960, 108958868923534266, 2551477805087525055, 57187304932168982070, 1233918981730653994884
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OFFSET
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2,2
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LINKS
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FORMULA
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[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,0,1152)/2.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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