A269136 - OEIS

%I #8 Apr 20 2020 19:49:37

%S 4,148,18556,8317996,14197016484,95884587957284,2621894498331024092,

%T 294433751149574057834796,137064853562490916405823252564,

%U 266206369700280385363973380215109284

%N Number of n X n 0..3 arrays with some element plus some horizontally, antidiagonally or vertically adjacent neighbor totalling three no more than once.

%C Diagonal of A269143.

%e Some solutions for n=3

%e ..2..2..3. .0..0..2. .2..1..1. .2..3..2. .0..0..1. .3..1..3. .0..1..3

%e ..3..2..3. .0..2..2. .0..0..1. .3..2..2. .1..1..3. .3..1..3. .3..1..3

%e ..3..2..2. .0..0..1. .1..1..1. .3..2..2. .0..2..2. .3..2..3. .1..3..1

%Y Cf. A269143.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 20 2016