A268806 Number of nX5 0..2 arrays with some element plus some horizontally, vertically or antidiagonally adjacent neighbor totalling two not more than once.
144, 772, 4158, 28452, 195384, 1316226, 8734264, 57302798, 372342650, 2400532536, 15373692036, 97900054556, 620374078660, 3914367133320, 24605301916568, 154148669247610, 962830699411796, 5997782979007294, 37271323919688010
Offset: 1
Keywords
Examples
Some solutions for n=4 ..0..0..1..0..1. .0..1..0..0..0. .2..1..2..2..1. .1..0..0..1..0 ..0..0..0..0..1. .0..0..0..1..0. .2..1..2..2..2. .0..0..1..0..0 ..1..0..1..0..0. .0..1..0..0..0. .2..2..2..2..2. .1..0..0..0..1 ..0..0..0..0..0. .1..0..0..0..0. .2..1..2..2..2. .0..0..1..0..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A268809.
Formula
Empirical: a(n) = 2*a(n-1) +41*a(n-2) +54*a(n-3) -509*a(n-4) -2182*a(n-5) -2830*a(n-6) +1766*a(n-7) +7914*a(n-8) +2584*a(n-9) -10583*a(n-10) -6092*a(n-11) +11506*a(n-12) +5348*a(n-13) -11688*a(n-14) -620*a(n-15) +9251*a(n-16) -4462*a(n-17) -3137*a(n-18) +4774*a(n-19) -2365*a(n-20) +338*a(n-21) +198*a(n-22) -106*a(n-23) +12*a(n-24) +4*a(n-25) -a(n-26) for n>29
Comments