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A157592 Half the number of length n integer sequences with sum zero and sum of squares 7200. 1
1, 3, 126, 23870, 2725455, 314174553, 29749465207, 2182715679324, 150186806030400, 10125676123572801, 666260841650613825, 42448715774998807794, 2597948199840416316530, 152089661374768398565935 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

LINKS

R. H. Hardin, Table of n, a(n) for n=2..50

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.

CROSSREFS

Sequence in context: A157562 A324152 A274314 * A213988 A159319 A086154

Adjacent sequences:  A157589 A157590 A157591 * A157593 A157594 A157595

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 02 2009

STATUS

approved

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Last modified June 27 04:16 EDT 2022. Contains 354888 sequences. (Running on oeis4.)