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Search: id:A157601
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| A157601 |
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Half the number of length n integer sequences with sum zero and sum of squares 9522. |
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+0
1
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| 1, 3, 450, 35490, 3461325, 429808743, 45598808332, 4382814679428, 396120762708465, 32858020705796385, 2495992345644237990, 177151945927883401410, 12079996873394323662971, 800952129262668313107765
(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,0,9522)/2.
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CROSSREFS
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Sequence in context: A086207 A092052 A139999 this_sequence A094454 A157587 A054702
Adjacent sequences: A157598 A157599 A157600 this_sequence A157602 A157603 A157604
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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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