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Search: id:A157586
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| A157586 |
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Half the number of length n integer sequences with sum zero and sum of squares 5832. |
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+0
1
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| 1, 3, 162, 16410, 1839645, 210928977, 17676193171, 1148671947972, 71262995700540, 4352863891098140, 258238261126722129, 14806140740844716211, 815211282605034375060, 42951699550186642926270, 2166061193994862365099390
(list; graph; listen)
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OFFSET
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2,2
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LINKS
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Ron Hardin, Table of n, a(n) for n=2..50
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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,0,5832)/2.
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CROSSREFS
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Sequence in context: A067322 A157440 A157559 this_sequence A042439 A030258 A154737
Adjacent sequences: A157583 A157584 A157585 this_sequence A157587 A157588 A157589
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KEYWORD
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nonn
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AUTHOR
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Ron Hardin (rhhardin(AT)att.net) Mar 02 2009
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