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A157563 Half the number of length n integer sequences with sum zero and sum of squares 1922. 1
1, 9, 198, 9930, 447345, 19373781, 801643164, 34613610228, 1445069106945, 53870000270295, 1838679236576886, 59112727361906010, 1820954720583759943, 54244177130219463765, 1568969312068377795960, 44074283494841644862536 (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,0,1922)/2.

CROSSREFS

Sequence in context: A110807 A019566 A338226 * A003026 A157594 A232276

Adjacent sequences:  A157560 A157561 A157562 * A157564 A157565 A157566

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 02 2009

STATUS

approved

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Last modified September 27 03:05 EDT 2021. Contains 347673 sequences. (Running on oeis4.)