A164750 Number of nX4 1..4 arrays with all 1s connected, all 2s connected, all 3s connected, all 4s connected, 1 in the upper left corner, 2 in the upper right corner, 3 in the lower left corner, and 4 in the lower right corner

33, 730, 8181, 66970, 454001, 2710440, 14765875, 75078360, 361767973, 1669896490, 7442607455, 32219919102, 136108600539, 563096090012, 2288108822659, 9153641479832, 36122611753603, 140843294581018, 543321531506705

Offset

2,1

Links

R. H. Hardin, Table of n, a(n) for n=2..21

Example

Some solutions for n=3
...1.3.3.2...1.1.2.2...1.2.2.2...1.3.3.2...1.2.2.2...1.1.1.2...1.1.1.2
...1.3.4.2...1.1.2.4...2.2.2.4...1.1.3.2...1.2.2.4...1.3.3.4...1.3.3.4
...3.3.4.4...3.1.1.4...3.3.2.4...3.3.3.4...3.3.4.4...3.3.3.4...3.3.4.4
------
...1.1.1.2...1.1.2.2...1.1.1.2...1.1.2.2...1.1.1.2...1.1.1.2...1.1.3.2
...3.3.2.2...3.1.2.4...4.4.4.4...1.1.1.1...1.3.1.2...1.3.1.4...3.1.3.2
...3.4.4.4...3.4.4.4...3.3.4.4...3.3.1.4...3.3.1.4...3.3.1.4...3.3.3.4

Crossrefs

Sequence in context: A025130 A081141 A021021 * A100788 A051565 A014931

Adjacent sequences: A164747 A164748 A164749 * A164751 A164752 A164753

Keyword

nonn

Author

R. H. Hardin Aug 24 2009

Status

approved