A209809 Number of (n+1)X4 0..3 arrays with every 2X2 subblock having two distinct values, and new values 0..3 introduced in row major order.

173, 2721, 43209, 712829, 11912459, 201392025, 3428713825, 58668627061, 1007251262049, 17332656663131, 298717962915543, 5153570546264489, 88972824040813647, 1536771179571237129, 26551969300854432109

Offset

1,1

Comments

Column 3 of A209814

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 26*a(n-1) -68*a(n-2) -1905*a(n-3) +6356*a(n-4) +40342*a(n-5) -117881*a(n-6) -302966*a(n-7) +604526*a(n-8) +940543*a(n-9) -1163096*a(n-10) -1137756*a(n-11) +834912*a(n-12) +402624*a(n-13) -124416*a(n-14)

Example

Some solutions for n=4
..0..1..0..1....0..0..1..0....0..0..0..0....0..0..1..0....0..0..0..1
..0..1..0..0....0..1..1..0....0..1..0..1....2..0..1..0....0..1..0..0
..0..0..0..1....0..0..0..1....0..0..0..0....2..0..1..0....0..0..0..1
..0..2..0..0....1..0..1..1....0..1..1..0....0..0..0..0....0..1..0..0
..0..2..0..1....1..0..0..0....0..0..0..1....1..1..0..2....0..0..0..1

Crossrefs

Sequence in context: A142849 A271978 A224794 * A185707 A185701 A138267

Adjacent sequences: A209806 A209807 A209808 * A209810 A209811 A209812

Keyword

nonn

Author

R. H. Hardin, Mar 13 2012

Status

approved