A268805 Number of nX4 0..2 arrays with some element plus some horizontally, vertically or antidiagonally adjacent neighbor totalling two not more than once.

60, 290, 1202, 5848, 28452, 135912, 640926, 2990786, 13835892, 63544542, 290056316, 1317009868, 5952527788, 26795651036, 120193389832, 537427198324, 2396207992178, 10656560102448, 47282655935580, 209348341875062

Offset

1,1

Comments

Column 4 of A268809.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +19*a(n-2) +10*a(n-3) -122*a(n-4) -320*a(n-5) -295*a(n-6) +8*a(n-7) +176*a(n-8) +20*a(n-9) -98*a(n-10) -6*a(n-11) +43*a(n-12) -6*a(n-13) -11*a(n-14) +6*a(n-15) -a(n-16) for n>19

Example

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

Crossrefs

Cf. A268809.

Sequence in context: A100151 A338109 A179811 * A146750 A298045 A063497

Adjacent sequences: A268802 A268803 A268804 * A268806 A268807 A268808

Keyword

nonn

Author

R. H. Hardin, Feb 13 2016

Status

approved