A240041 Number of nX2 0..3 arrays with no element equal to zero plus the sum of elements to its left or zero plus the sum of elements above it or zero plus the sum of the elements diagonally to its northwest or one plus the sum of the elements antidiagonally to its northeast, modulo 4.
2, 4, 10, 22, 50, 119, 276, 637, 1473, 3355, 7682, 17497, 39777, 90406, 205111, 465359, 1054871, 2390302, 5415591, 12265608, 27777095, 62895884, 142401878, 322392952, 729835421, 1652150714, 3739914222, 8465684665, 19162662378, 43375394510
Offset: 1
Keywords
Examples
All solutions for n=3 ..3..2....3..2....2..3....3..2....2..3....3..2....2..3....3..2....3..2....2..3 ..2..0....1..0....3..0....1..0....1..0....1..0....3..0....2..0....2..0....3..0 ..2..0....2..0....2..0....2..3....2..0....3..0....3..0....2..3....3..0....3..2
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = 3*a(n-2) +10*a(n-3) +3*a(n-4) -12*a(n-5) -46*a(n-6) -36*a(n-7) +12*a(n-8) +107*a(n-9) +87*a(n-10) +2*a(n-11) -145*a(n-12) -138*a(n-13) -48*a(n-14) +147*a(n-15) +185*a(n-16) +89*a(n-17) -94*a(n-18) -210*a(n-19) -111*a(n-20) +40*a(n-21) +176*a(n-22) +85*a(n-23) +30*a(n-24) -77*a(n-25) -47*a(n-26) -57*a(n-27) +14*a(n-29) +21*a(n-30) +14*a(n-31) -3*a(n-32) +2*a(n-33) -5*a(n-34) +a(n-35) +2*a(n-36) +a(n-37) -a(n-38) for n>40
Comments