A241284 Number of 2Xn 0..3 arrays with no element equal to one plus the sum of elements to its left or zero plus the sum of the elements above it or one plus the sum of the elements diagonally to its northwest or one plus the sum of the elements antidiagonally to its northeast, modulo 4.
4, 3, 5, 13, 17, 35, 90, 141, 288, 670, 1101, 2265, 4995, 8474, 17477, 37329, 64894, 133967, 279966, 496683, 1023868, 2105032, 3799717, 7810452, 15858460, 29052053, 59504463, 119660776, 221989407, 452920894, 904106577, 1695187559, 3445124586
Offset: 1
Keywords
Examples
Some solutions for n=4 ..3..3..2..3....3..2..3..2....3..3..2..3....3..3..2..3....3..3..2..2 ..2..1..1..0....2..1..1..3....2..1..3..0....2..2..3..2....2..1..1..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = a(n-1) +a(n-2) +7*a(n-3) -8*a(n-4) -7*a(n-5) +9*a(n-7) +10*a(n-8) -24*a(n-9) +5*a(n-10) +29*a(n-11) -18*a(n-12) -10*a(n-13) -10*a(n-14) +16*a(n-15) +12*a(n-16) -12*a(n-17) for n>18
Comments