cp's OEIS Frontend

A225351 Number of 11Xn -1,1 arrays such that the sum over i=1..11,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 11 fore-aft positions so that there are no turning moments on the ship).

%I A225351 #8 Jun 02 2025 08:33:58
%S A225351 0,1113,0,103583,0,2102597,0,20044255,0,121558241,0,545572495,0,
%T A225351 1975264495,0,6087969941,0,16555930825,0,40733826807,0,92339940289,0,
%U A225351 195519292147,0,390766431925,0,743286869427,0,1354483437063,0
%N A225351 Number of 11Xn -1,1 arrays such that the sum over i=1..11,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 11 fore-aft positions so that there are no turning moments on the ship).
%C A225351 Row 11 of A225345
%H A225351 R. H. Hardin, <a href="/A225351/b225351.txt">Table of n, a(n) for n = 1..277</a>
%F A225351 Empirical: a(n) = 2*a(n-4) +a(n-6) -a(n-12) -3*a(n-14) -2*a(n-16) +3*a(n-24) +4*a(n-26) +2*a(n-28) +3*a(n-30) +2*a(n-32) -3*a(n-34) -5*a(n-36) -4*a(n-38) -5*a(n-40) -4*a(n-42) -a(n-44) +2*a(n-46) +4*a(n-48) +6*a(n-50) +6*a(n-52) +4*a(n-54) +2*a(n-56) -a(n-58) -4*a(n-60) -5*a(n-62) -4*a(n-64) -5*a(n-66) -3*a(n-68) +2*a(n-70) +3*a(n-72) +2*a(n-74) +4*a(n-76) +3*a(n-78) -2*a(n-86) -3*a(n-88) -a(n-90) +a(n-96) +2*a(n-98) -a(n-102)
%e A225351 Some solutions for n=4
%e A225351 .-1.-1.-1..1....1..1..1..1...-1.-1.-1..1....1..1..1..1...-1..1..1..1
%e A225351 .-1.-1..1..1...-1.-1.-1..1...-1.-1..1..1...-1.-1.-1..1...-1.-1.-1.-1
%e A225351 ..1..1..1..1...-1.-1.-1..1...-1.-1..1..1...-1.-1..1..1...-1..1..1..1
%e A225351 .-1.-1..1..1...-1..1..1..1...-1..1..1..1...-1.-1.-1..1...-1.-1..1..1
%e A225351 .-1.-1.-1.-1...-1.-1..1..1...-1.-1..1..1...-1.-1..1..1...-1.-1.-1..1
%e A225351 ..1..1..1..1...-1.-1.-1..1...-1.-1..1..1...-1.-1..1..1...-1..1..1..1
%e A225351 .-1.-1..1..1...-1.-1..1..1...-1..1..1..1...-1.-1.-1.-1...-1..1..1..1
%e A225351 .-1.-1..1..1...-1.-1.-1.-1...-1.-1.-1..1...-1.-1..1..1...-1.-1.-1..1
%e A225351 .-1.-1.-1..1...-1.-1..1..1...-1..1..1..1....1..1..1..1...-1..1..1..1
%e A225351 .-1.-1.-1.-1...-1..1..1..1...-1.-1..1..1...-1.-1..1..1...-1.-1.-1.-1
%e A225351 ..1..1..1..1...-1..1..1..1...-1.-1.-1..1...-1.-1..1..1...-1..1..1..1
%K A225351 nonn
%O A225351 1,2
%A A225351 _R. H. Hardin_ May 05 2013