A296537 Number of nX4 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 2 or 4 neighboring 1s.

1, 8, 37, 126, 431, 1554, 5601, 20036, 71722, 256991, 920643, 3297782, 11813230, 42316775, 151584446, 542999656, 1945111540, 6967686648, 24959322680, 89408160916, 320273851760, 1147270357089, 4109699588023, 14721578711022

Offset

1,2

Comments

Column 4 of A296541.

Links

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

Formula

Empirical: a(n) = 6*a(n-1) -13*a(n-2) +21*a(n-3) -22*a(n-4) +7*a(n-5) +18*a(n-6) -37*a(n-7) -34*a(n-8) +111*a(n-9) -210*a(n-10) +91*a(n-11) +161*a(n-12) -194*a(n-13) +84*a(n-14) +464*a(n-15) -73*a(n-16) +283*a(n-17) +265*a(n-18) -165*a(n-19) -208*a(n-20) -363*a(n-21) -705*a(n-22) -701*a(n-23) -687*a(n-24) -589*a(n-25) -418*a(n-26) -171*a(n-27) -30*a(n-28) +142*a(n-29) +214*a(n-30) +244*a(n-31) +218*a(n-32) +175*a(n-33) +114*a(n-34) +69*a(n-35) +34*a(n-36) +14*a(n-37) +4*a(n-38) +a(n-39)

Example

Some solutions for n=7
..0..0..1..0. .0..1..0..0. .1..1..0..0. .1..1..1..0. .0..1..1..0
..1..1..1..0. .1..1..0..0. .1..0..0..0. .1..1..0..0. .0..1..0..0
..1..0..0..1. .0..0..1..0. .0..1..1..1. .1..0..0..0. .0..0..0..0
..0..0..1..1. .1..1..1..0. .0..1..1..0. .0..1..1..0. .0..0..0..0
..0..0..0..0. .1..0..0..0. .0..1..0..0. .0..1..0..0. .1..1..1..0
..0..0..1..0. .0..1..0..0. .0..0..0..1. .1..1..0..0. .1..1..0..0
..0..1..1..0. .1..1..0..0. .0..0..1..1. .0..0..0..0. .1..0..0..0

Crossrefs

Cf. A296541.

Sequence in context: A250168 A244870 A309281 * A052387 A001780 A258476

Adjacent sequences: A296534 A296535 A296536 * A296538 A296539 A296540

Keyword

nonn

Author

R. H. Hardin, Dec 15 2017

Status

approved