A301325 Number of nX3 0..1 arrays with every element equal to 0, 2, 3, 5 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

1, 2, 7, 18, 25, 89, 233, 552, 1559, 4206, 11455, 31045, 85231, 232290, 634523, 1734730, 4739443, 12951941, 35393517, 96729068, 264330489, 722375126, 1974122009, 5394894605, 14743271905, 40290668634, 110107068099, 300902363502

Offset

1,2

Comments

Column 3 of A301330.

Links

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

Formula

Empirical: a(n) = a(n-1) +3*a(n-2) +6*a(n-3) -6*a(n-5) -9*a(n-6) +7*a(n-7) -15*a(n-8) -14*a(n-9) -20*a(n-10) +30*a(n-11) +3*a(n-12) +47*a(n-13) -67*a(n-14) +38*a(n-15) +15*a(n-16) -65*a(n-17) +106*a(n-18) -83*a(n-19) +24*a(n-20) +13*a(n-21) -32*a(n-22) +29*a(n-23) -11*a(n-24) +3*a(n-26) -3*a(n-27) +a(n-28) for n>29

Example

Some solutions for n=5
..0..0..1. .0..0..0. .0..0..0. .0..1..1. .0..0..1. .0..1..0. .0..0..1
..0..1..1. .0..1..0. .0..1..0. .1..1..1. .0..1..1. .1..1..1. .0..1..1
..0..1..0. .0..0..1. .0..0..0. .1..0..0. .0..0..0. .1..1..0. .0..0..0
..0..0..0. .1..1..1. .1..1..0. .0..1..0. .0..1..0. .0..0..0. .0..1..0
..0..0..1. .1..1..0. .1..0..0. .0..0..1. .0..0..0. .0..0..1. .0..0..1

Crossrefs

Cf. A301330.

Sequence in context: A217253 A268837 A104310 * A001114 A107615 A195605

Adjacent sequences: A301322 A301323 A301324 * A301326 A301327 A301328

Keyword

nonn

Author

R. H. Hardin, Mar 18 2018

Status

approved