cp's OEIS Frontend

A194781 Number of lower triangles of a (2n+1)X(2n+1) 0..n array with new values introduced in row major order 0..n and no element unequal to more than one horizontal or vertical neighbor.

%I A194781 #6 Jul 22 2025 12:36:28
%S A194781 6,41,265,1736,11857,85007,639753,5045602,41615156,358185389,
%T A194781 3210667479,29914284821,289187621887
%N A194781 Number of lower triangles of a (2n+1)X(2n+1) 0..n array with new values introduced in row major order 0..n and no element unequal to more than one horizontal or vertical neighbor.
%C A194781 Row 3 of A194778
%e A194781 Some solutions for n=2 containing a 2
%e A194781 ..0..........0..........0..........0..........0..........0..........0
%e A194781 ..1.1........1.1........1.1........0.0........1.1........1.1........0.1
%e A194781 ..1.1.2......1.1.1......1.1.1......1.1.1......1.1.1......1.1.2......0.1.1
%e A194781 ..1.1.2.2....1.1.1.1....1.1.1.2....1.1.1.1....2.2.2.2....1.1.2.2....0.1.1.1
%e A194781 ..1.1.2.2.1..2.2.2.2.2..1.1.1.2.2..1.1.1.1.2..2.2.2.2.0..1.1.2.2.0..0.1.1.1.2
%K A194781 nonn
%O A194781 1,1
%A A194781 _R. H. Hardin_ Sep 02 2011