A183547 Number of n X 2 0..2 arrays with each element equal to either the maximum or the minimum of its horizontal and vertical neighbors.
3, 15, 71, 299, 1325, 5845, 25785, 113841, 502523, 2218399, 9793287, 43233099, 190855613, 842545925, 3719480233, 16419916497, 72486917979, 319998782959, 1412657953559, 6236281512443, 27530519336653, 121535484480133
Offset: 1
Keywords
Examples
Some solutions for 3 X 2: ..0..0....2..2....1..1....2..2....1..1....0..0....2..1....1..1....0..0....2..2 ..1..0....1..2....2..1....0..0....0..1....1..1....2..1....0..0....2..0....0..2 ..1..1....1..1....2..1....1..1....0..1....1..1....2..1....1..1....2..0....0..2
Links
- R. H. Hardin, Table of n, a(n) for n = 1..200
Crossrefs
Cf. A183554.
Formula
Empirical: a(n) = 5*a(n-1) - 3*a(n-2) + 4*a(n-3) - 9*a(n-4) - 13*a(n-6) + 8*a(n-7) + 4*a(n-8) + 7*a(n-9) + 2*a(n-10).
Empirical g.f.: x*(3 + 5*x^2 - 23*x^3 + 10*x^4 - 32*x^5 + 17*x^6 + 13*x^7 + 9*x^8 + 10*x^9) / (1 - 5*x + 3*x^2 - 4*x^3 + 9*x^4 + 13*x^6 - 8*x^7 - 4*x^8 - 7*x^9 - 2*x^10). - Colin Barker, Mar 29 2018
Comments