A269056 Number of 5Xn 0..2 arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two not more than once.
243, 2430, 17346, 183072, 1643376, 15547380, 140497512, 1273499256, 11354964888, 100764874440, 886829123676, 7765850889120, 67643548943508, 586749197487720, 5069733374448192, 43657996370224608, 374818434125094900
Offset: 1
Keywords
Examples
Some solutions for n=4 ..0..1..2..1. .1..0..1..0. .0..1..2..1. .0..0..1..0. .1..1..0..0 ..2..1..2..1. .0..0..1..2. .0..1..0..1. .1..2..1..2. .0..0..0..0 ..2..1..0..2. .1..0..1..2. .0..1..2..1. .2..2..2..2. .0..0..0..1 ..0..1..2..1. .0..0..1..0. .0..1..0..0. .2..1..2..1. .0..0..0..1 ..0..1..2..2. .0..0..1..0. .0..0..0..0. .0..1..2..2. .1..0..0..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A269052.
Formula
Empirical: a(n) = 12*a(n-1) +26*a(n-2) -566*a(n-3) -123*a(n-4) +8804*a(n-5) -4121*a(n-6) -59620*a(n-7) +55115*a(n-8) +183692*a(n-9) -256127*a(n-10) -211910*a(n-11) +498819*a(n-12) -48036*a(n-13) -371692*a(n-14) +214008*a(n-15) +43848*a(n-16) -64656*a(n-17) +8640*a(n-18) +5184*a(n-19) -1296*a(n-20) for n>22
Comments