A184038 1/16 the number of (n+1) X 9 0..3 arrays with all 2 X 2 subblocks having the same four values.
1225, 1237, 1258, 1300, 1378, 1534, 1834, 2434, 3610, 5962, 10618, 19930, 38458, 75514, 149434, 297274, 592570, 1183162, 2363578, 4724410, 9444538, 18884794, 37762234, 75517114, 151020730, 302027962, 604030138, 1208034490, 2416018618
Offset: 1
Keywords
Examples
Some solutions for 3 X 9: ..3..0..3..1..3..0..3..1..3....0..0..3..1..3..1..0..0..0 ..1..1..1..0..1..1..1..0..1....3..1..0..0..0..0..3..1..3 ..3..0..3..1..3..0..3..1..3....0..0..3..1..3..1..0..0..0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..53
Formula
Empirical: a(n) = 3*a(n-1) - 6*a(n-3) + 4*a(n-4).
Conjectures from Colin Barker, Apr 10 2018: (Start)
G.f.: x*(1225 - 2438*x - 2453*x^2 + 4876*x^3) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)).
a(n) = 9*2^(n/2-1) + 9*2^(n-1) + 1210 for n even.
a(n) = 9*2^(n-1) + 3*2^((n+1)/2) + 1210 for n odd.
(End)
Comments