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A225350 Number of 10Xn -1,1 arrays such that the sum over i=1..10,j=1..n of i*x(i,j) is zero, the sum of x(i,j) is zero, and rows are nondecreasing (number of ways to distribute n-across galley oarsmen left-right at 10 fore-aft positions so that there are no turning moments on the ship) 1
0, 443, 0, 24893, 0, 360909, 0, 2676331, 0, 13280209, 0, 50435657, 0, 158259755, 0, 430394067, 0, 1047240813, 0, 2331232209, 0, 4825180007, 0, 9399464741, 0, 17394354077, 0, 30804515135, 0, 52513235123, 0, 86584738985, 0, 138623327831, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row 10 of A225345

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = a(n-2) +a(n-4) -a(n-10) -a(n-14) -a(n-20) +2*a(n-24) +a(n-26) +a(n-28) +a(n-30) -a(n-34) -a(n-36) -a(n-38) -2*a(n-40) -a(n-42) -a(n-44) +a(n-46) +a(n-48) +2*a(n-50) +a(n-52) +a(n-54) +a(n-56) -a(n-60) -a(n-62) -a(n-64) -2*a(n-66) +a(n-70) +a(n-76) +a(n-80) -a(n-86) -a(n-88) +a(n-90)

EXAMPLE

Some solutions for n=4

..1..1..1..1...-1.-1.-1.-1...-1.-1.-1..1...-1.-1.-1..1...-1.-1.-1.-1

.-1.-1.-1.-1....1..1..1..1...-1..1..1..1...-1..1..1..1...-1..1..1..1

.-1.-1.-1..1...-1.-1.-1.-1...-1..1..1..1...-1.-1.-1..1...-1.-1..1..1

.-1..1..1..1....1..1..1..1...-1.-1.-1..1...-1.-1..1..1....1..1..1..1

..1..1..1..1....1..1..1..1...-1.-1..1..1...-1..1..1..1...-1..1..1..1

.-1.-1.-1.-1...-1..1..1..1...-1.-1..1..1...-1..1..1..1...-1.-1.-1.-1

.-1.-1.-1..1...-1.-1.-1.-1...-1..1..1..1...-1..1..1..1...-1.-1.-1..1

.-1.-1.-1..1...-1.-1.-1..1...-1.-1.-1..1...-1.-1.-1..1....1..1..1..1

..1..1..1..1...-1.-1.-1.-1...-1.-1.-1..1...-1.-1.-1.-1...-1.-1..1..1

.-1.-1..1..1....1..1..1..1...-1..1..1..1...-1..1..1..1...-1.-1.-1..1

CROSSREFS

Sequence in context: A018237 A264270 A098256 * A171392 A105980 A031519

Adjacent sequences:  A225347 A225348 A225349 * A225351 A225352 A225353

KEYWORD

nonn

AUTHOR

R. H. Hardin May 05 2013

STATUS

approved

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Last modified May 10 20:33 EDT 2021. Contains 343780 sequences. (Running on oeis4.)