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A157592
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Half the number of length n integer sequences with sum zero and sum of squares 7200.
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1
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1, 3, 126, 23870, 2725455, 314174553, 29749465207, 2182715679324, 150186806030400, 10125676123572801, 666260841650613825, 42448715774998807794, 2597948199840416316530, 152089661374768398565935
(list; graph; refs; listen; history; internal format)
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OFFSET
| 2,2
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LINKS
| R. H. Hardin, Table of n, a(n) for n=2..50
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FORMULA
| [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,0,7200)/2.
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CROSSREFS
| Sequence in context: A157547 A160879 A157562 * A159319 A086154 A133122
Adjacent sequences: A157589 A157590 A157591 * A157593 A157594 A157595
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KEYWORD
| nonn
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AUTHOR
| R. H. Hardin (rhhardin(AT)att.net) Mar 02 2009
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