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A225352 Number of 12Xn -1,1 arrays such that the sum over i=1..12,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 12 fore-aft positions so that there are no turning moments on the ship) 1
58, 2837, 47990, 437763, 2680534, 12439855, 47084448, 152452967, 436320984, 1129965973, 2694285574, 5993361143, 12566218452, 25037146431, 47716202440, 87454967053, 154837885246, 265807450011, 443841357932, 722822838305 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 12 of A225345

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) +a(n-2) -a(n-5) -a(n-7) +a(n-14) +2*a(n-15) +a(n-16) -a(n-19) -a(n-20) -a(n-21) -2*a(n-22) -a(n-23) -a(n-24) -a(n-26) +2*a(n-27) +2*a(n-28) +2*a(n-29) +2*a(n-30) +a(n-31) +a(n-32) -a(n-34) -a(n-35) -2*a(n-36) -2*a(n-37) -2*a(n-38) -2*a(n-39) +a(n-40) +a(n-42) +a(n-43) +2*a(n-44) +a(n-45) +a(n-46) +a(n-47) -a(n-50) -2*a(n-51) -a(n-52) +a(n-59) +a(n-61) -a(n-64) -a(n-65) +a(n-66)

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

.-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: A017721 A280111 A281031 * A278097 A299467 A334935

Adjacent sequences:  A225349 A225350 A225351 * A225353 A225354 A225355

KEYWORD

nonn

AUTHOR

R. H. Hardin May 05 2013

STATUS

approved

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Last modified May 15 18:26 EDT 2021. Contains 343920 sequences. (Running on oeis4.)