A211842 Number of nonnegative integer arrays of length n+3 with new values 0 upwards introduced in order, no three adjacent elements all unequal, and containing the value 2.

1, 5, 19, 63, 196, 588, 1731, 5049, 14689, 42809, 125364, 369678, 1099339, 3300091, 10006487, 30658799, 94932890, 297079702, 939477265, 3001846219, 9689289277, 31586215805, 103968208826, 345457027212, 1158435912189, 3919502591649

Offset: 1

Author

R. H. Hardin Apr 22 2012

Keywords

• nonn

Comments

Column 1 of A211849.

Examples

			Some solutions for n=3
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..1....1....1....1....0....1....0....1....0....1....1....1....0....1....0....1
..1....1....1....1....1....0....1....1....1....0....1....1....0....0....1....1
..1....1....1....2....1....0....0....0....1....1....2....2....1....0....1....2
..2....1....2....2....2....0....0....0....2....1....1....2....1....2....1....2
..2....2....1....3....2....2....2....2....1....2....2....1....2....2....2....2
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Crossrefs

Cf. A211849.