A145809 - OEIS

A145809

Number of islands of ones fitting in an n X n array with all ones connected only either three adjacent vertically or three adjacent horizontally.

%I #3 Mar 31 2012 12:35:08

%S 0,0,2,2,4,6,8,10,14,15,20,24

%N Number of islands of ones fitting in an n X n array with all ones connected only either three adjacent vertically or three adjacent horizontally.

%e 8 X 8 example with 10 islands

%e .0.1.1.1.0.1.1.1

%e .1.0.0.0.0.0.0.0

%e .1.0.0.0.0.1.1.1

%e .1.0.1.1.1.0.0.0

%e .0.0.0.0.0.1.1.1

%e .1.0.1.1.1.0.0.0

%e .1.0.0.0.0.1.1.1

%e .1.0.1.1.1.0.0.0

%K nonn

%O 1,3

%A _R. H. Hardin_, Oct 20 2008