A194022 - OEIS

%I #8 Dec 09 2017 03:57:00

%S 0,0,0,0,21,560,6425,47385,262382,1180469,4530030,15317274,46696163,

%T 130554918,339126948,826821895,1907572610,4192279515,8824669582,

%U 17873749440,34969097933,66304228516,122186400487,219382723103

%N Number of ways to arrange 8 points on an n X n X n triangular grid on an isosceles triangle so that it balances at the midpoint of its central altitude.

%C Column 8 of A194024.

%H R. H. Hardin, <a href="/A194022/b194022.txt">Table of n, a(n) for n = 1..31</a>

%e Some solutions for 5 X 5 X 5:

%e ......1..........1..........1..........1..........1..........1..........1

%e .....1.1........1.1........1.1........1.1........1.1........1.0........1.1

%e ....0.1.1......1.1.0......1.1.0......0.1.1......1.0.1......1.1.1......0.1.1

%e ...1.0.0.1....0.0.1.1....1.0.0.1....0.1.1.0....1.0.1.0....1.0.1.1....0.1.0.1

%e ..0.1.0.0.0..0.1.0.0.0..0.0.0.1.0..0.1.0.0.0..0.0.0.1.0..0.0.0.0.0..1.0.0.0.0

%K nonn

%O 1,5

%A _R. H. Hardin_, Aug 12 2011