A241115 Number of nX3 0..3 arrays with no element equal to exactly three horizontal or vertical neighbors, with new values 0..3 introduced in row major order.
5, 178, 9918, 587555, 35000157, 2085879115, 124315318217, 7409032909403, 441568937568818, 26316947602316573, 1568456640467509976, 93478023005207665450, 5571171404819117025366, 332034737407500793137773
Offset: 1
Keywords
Examples
Some solutions for n=3 ..0..1..1....0..1..2....0..0..1....0..0..1....0..1..0....0..1..2....0..1..2 ..2..2..2....0..0..2....2..2..2....1..2..2....2..3..2....2..1..0....0..1..0 ..3..1..3....1..2..0....0..3..0....2..3..0....0..0..3....2..3..3....1..0..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = 60*a(n-1) -7*a(n-2) -972*a(n-3) -2112*a(n-4) -2660*a(n-5) +12008*a(n-6) +48742*a(n-7) +35629*a(n-8) -20302*a(n-9) -27711*a(n-10) -65688*a(n-11) -146133*a(n-12) -130104*a(n-13) -24426*a(n-14) +56268*a(n-15) +56538*a(n-16) +13284*a(n-17) -5103*a(n-18) -5346*a(n-19) -1458*a(n-20) for n>21
Comments