A275127 Number of nX4 0..2 arrays with no element equal to any value at offset (-2,-2) (-1,0) or (-1,1) and new values introduced in order 0..2.
14, 64, 174, 568, 2178, 8321, 31772, 121707, 466252, 1783920, 6825273, 26122839, 99981686, 382636173, 1464403303, 5604594713, 21449747744, 82091326930, 314176968483, 1202409074708, 4601819411125, 17611921823170, 67403757335393
Offset: 1
Keywords
Examples
Some solutions for n=4 ..0..1..1..2. .0..1..1..2. .0..0..0..1. .0..0..1..1. .0..0..0..1 ..2..0..0..1. .2..0..0..0. .1..1..2..2. .1..2..2..0. .2..1..2..2 ..1..2..2..2. .1..1..1..2. .2..0..1..1. .0..1..1..1. .0..0..1..1 ..0..1..0..1. .2..2..0..1. .1..2..0..0. .2..0..2..0. .2..2..0..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A275131.
Formula
Empirical: a(n) = 5*a(n-1) -9*a(n-2) +19*a(n-3) -9*a(n-4) -9*a(n-5) +87*a(n-6) -46*a(n-7) -84*a(n-8) +7*a(n-9) -59*a(n-10) -45*a(n-11) +31*a(n-12) +23*a(n-13) +4*a(n-14) -a(n-15) -a(n-16) +a(n-17) for n>20
Comments