cp's OEIS Frontend

A225339 Number of nX3 -1,1 arrays such that the sum over i=1..n,j=1..3 of i*x(i,j) is zero, the sum of x(i,j) is zero, and rows are nondecreasing (number of ways to distribute 3-across galley oarsmen left-right at n fore-aft positions so that there are no turning moments on the ship).

%I A225339 #6 Jun 02 2025 08:32:44
%S A225339 0,0,0,6,0,0,0,410,0,0,0,47990,0,0,0,7030132,0,0,0,1163743294,0,0,0,
%T A225339 208310242542,0,0,0,39371238885750,0,0,0,7745062224896578,0,0,0,
%U A225339 1571069270148096124,0,0,0,326518765865030556374,0,0,0
%N A225339 Number of nX3 -1,1 arrays such that the sum over i=1..n,j=1..3 of i*x(i,j) is zero, the sum of x(i,j) is zero, and rows are nondecreasing (number of ways to distribute 3-across galley oarsmen left-right at n fore-aft positions so that there are no turning moments on the ship).
%C A225339 Column 3 of A225345
%H A225339 R. H. Hardin, <a href="/A225339/b225339.txt">Table of n, a(n) for n = 1..159</a>
%e A225339 All solutions for n=4
%e A225339 ..1..1..1...-1.-1.-1...-1..1..1...-1..1..1...-1.-1..1...-1.-1..1
%e A225339 .-1.-1.-1....1..1..1...-1.-1..1...-1.-1.-1....1..1..1...-1..1..1
%e A225339 .-1.-1.-1....1..1..1...-1.-1..1....1..1..1...-1.-1.-1...-1..1..1
%e A225339 ..1..1..1...-1.-1.-1...-1..1..1...-1.-1..1...-1..1..1...-1.-1..1
%K A225339 nonn
%O A225339 1,4
%A A225339 _R. H. Hardin_ May 05 2013