A239820 Number of 2Xn 0..3 arrays with no element equal to zero plus the sum of elements to its left or one plus the sum of the elements above it, modulo 4.
5, 23, 132, 729, 3951, 21602, 118253, 646306, 3532732, 19315270, 105601487, 577330665, 3156353205, 17256335056, 94343160597, 515789128277, 2819903064231, 15416868881838, 84286524854294, 460808121256380, 2519312876415017
Offset: 1
Keywords
Examples
Some solutions for n=5 ..3..0..0..0..0....3..2..3..2..3....3..0..0..2..3....3..0..2..0..2 ..2..0..3..0..3....2..0..1..2..2....2..3..2..0..1....1..0..2..0..1
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Formula
Empirical: a(n) = 9*a(n-1) -28*a(n-2) +74*a(n-3) -181*a(n-4) +236*a(n-5) -261*a(n-6) +234*a(n-7) +200*a(n-8) -279*a(n-9) +104*a(n-10) -268*a(n-11) -36*a(n-12) +156*a(n-13) +104*a(n-14) -32*a(n-15) -16*a(n-16)
Comments