A218199 Hilltop maps: number of n X 1 binary arrays indicating the locations of corresponding elements not exceeded by any horizontal or vertical neighbor in a random 0..2 n X 1 array

1, 3, 7, 13, 25, 49, 97, 191, 375, 737, 1449, 2849, 5601, 11011, 21647, 42557, 83665, 164481, 323361, 635711, 1249775, 2456993, 4830321, 9496161, 18668961, 36702211, 72154647, 141852301, 278874281, 548252401, 1077835841, 2118969471, 4165784295

Offset

1,2

Comments

Column 1 of A218206.

Links

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

Formula

Empirical: a(n) = a(n-1) +a(n-2) +a(n-3) +a(n-4) +a(n-5).

Empirical g.f.: x*(1 + x + x^2)^2 / (1 - x - x^2 - x^3 - x^4 - x^5). - Colin Barker, Feb 18 2018

Example

All solutions for n=3:
..1....0....1....1....0....0....1
..0....0....1....1....1....1....0
..1....1....0....1....1....0....0

Crossrefs

cf. A102026.

Sequence in context: A336726 A201081 A017994 * A275788 A169914 A078000

Adjacent sequences: A218196 A218197 A218198 * A218200 A218201 A218202

Keyword

nonn

Author

R. H. Hardin, Oct 23 2012

Status

approved