A202883 Number of n X 2 0..2 arrays with every nonzero element less than or equal to some horizontal or vertical neighbor.
3, 35, 265, 1849, 13345, 96941, 701275, 5071167, 36689027, 265439091, 1920308033, 13892446697, 100505282121, 727107537885, 5260271847715, 38055531396239, 275313438949691, 1991760080088995, 14409424470217081, 104245243244589977
Offset: 1
Keywords
Examples
Some solutions for n=5: 2 0 2 1 2 0 0 0 0 0 0 1 2 2 2 1 1 2 2 2 2 0 2 1 2 2 1 1 0 2 2 2 2 1 2 2 1 2 1 1 0 2 2 1 2 2 1 0 0 2 0 1 0 0 2 0 1 2 2 1 0 2 2 0 0 0 2 1 2 2 1 1 2 0 0 1 2 2 2 0 0 1 1 0 1 1 2 1 2 1 2 2 2 1 1 1 0 1 1 0
Links
- R. H. Hardin, Table of n, a(n) for n = 1..210
Crossrefs
Cf. A202889.
Formula
Empirical: a(n) = 6*a(n-1) +2*a(n-2) +46*a(n-3) +25*a(n-4) +36*a(n-5).
Empirical g.f.: (3 + 17*x + 49*x^2 + 51*x^3 + 36*x^4) / (1 - 6*x - 2*x^2 - 46*x^3 - 25*x^4 - 36*x^5). - Colin Barker, Jun 02 2018
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