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A157542 Half the number of length n integer sequences with sum zero and sum of squares 200. 1
1, 3, 42, 930, 17685, 265041, 3668483, 44840097, 529728300, 5955342987, 65311345275, 699155920398, 7170690213960, 69964606094670, 652763403442422, 5868431782886486, 51137730082075059, 433379839761592641 (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,0,200)/2.

CROSSREFS

Sequence in context: A092470 A336572 A206820 * A078601 A268621 A218308

Adjacent sequences:  A157539 A157540 A157541 * A157543 A157544 A157545

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 02 2009

STATUS

approved

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Last modified May 24 08:57 EDT 2022. Contains 354026 sequences. (Running on oeis4.)