A240456 Number of nX2 0..3 arrays with no element equal to one plus the sum of elements to its left or three plus the sum of elements above it or one plus the sum of the elements diagonally to its northwest, modulo 4.
4, 21, 102, 476, 2200, 10123, 46471, 213000, 975380, 4464474, 20429739, 93474260, 427645941, 1956395954, 8949898045, 40942368765, 187294120155, 856787747966, 3919414321141, 17929510264717, 82019155503670, 375199231601451
Offset: 1
Keywords
Examples
Some solutions for n=4 ..2..0....2..0....0..2....2..2....0..0....2..2....2..2....2..0....0..2....2..2 ..0..2....0..0....2..0....2..2....2..2....0..0....2..2....3..2....2..2....3..2 ..3..3....0..0....3..2....2..0....3..2....2..2....0..2....2..2....2..0....3..2 ..3..1....2..2....3..1....2..2....3..2....0..2....0..3....0..0....2..0....2..2
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = 8*a(n-1) -20*a(n-2) +34*a(n-3) -84*a(n-4) +92*a(n-5) -68*a(n-6) +222*a(n-7) +13*a(n-8) -251*a(n-9) +25*a(n-10) -495*a(n-11) +485*a(n-12) -44*a(n-13) -180*a(n-14) +554*a(n-15) -648*a(n-16) +14*a(n-17) +152*a(n-18) -190*a(n-19) -140*a(n-20) +397*a(n-21) -273*a(n-22) +75*a(n-23) +167*a(n-24) -136*a(n-25) +27*a(n-26)
Comments