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 A157547 Half the number of length n integer sequences with sum zero and sum of squares 450. 1
 1, 3, 126, 2170, 37335, 921333, 21967484, 466292604, 9161931075, 164162481681, 2705726857350, 41747317681290, 619096670144225, 8923605271290360, 124998845674120920, 1699006653803990456, 22382667992161145863 (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,0,450)/2. CROSSREFS Sequence in context: A114877 A152859 A241647 * A160879 A157562 A324152 Adjacent sequences: A157544 A157545 A157546 * A157548 A157549 A157550 KEYWORD nonn AUTHOR R. H. Hardin Mar 02 2009 STATUS approved

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Last modified December 4 16:41 EST 2022. Contains 358563 sequences. (Running on oeis4.)