A198620 Number of n X 1 0..5 arrays with values 0..5 introduced in row major order and each element equal to at least one horizontal or vertical neighbor.

0, 1, 1, 2, 3, 6, 11, 23, 47, 103, 226, 518, 1200, 2866, 6939, 17184, 43133, 110122, 284485, 744297, 1965907, 5240825, 14072796, 38039586, 103368602, 282201932, 773327639, 2126010274, 5860104847, 16188449006, 44801184159, 124173477355

Offset

1,4

Comments

Column 1 of A198627.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 5*a(n-1) +a(n-2) -34*a(n-3) +20*a(n-4) +80*a(n-5) -51*a(n-6) -81*a(n-7) +31*a(n-8) +30*a(n-9) for n>10.

Empirical g.f.: x^2*(1 - 4*x - 4*x^2 + 26*x^3 + 3*x^4 - 54*x^5 - 5*x^6 + 37*x^7 + 11*x^8) / ((1 - x)*(1 + x)*(1 - 2*x)*(1 - x - x^2)*(1 - x - 3*x^2)*(1 - x - 5*x^2)). - Colin Barker, May 14 2018

Example

All solutions for n=4:
..0....0
..0....0
..0....1
..0....1

Crossrefs

Cf. A198627.

Sequence in context: A090344 A277795 A198662 * A198648 A198655 A211694

Adjacent sequences: A198617 A198618 A198619 * A198621 A198622 A198623

Keyword

nonn

Author

R. H. Hardin, Oct 27 2011

Status

approved