A218639 Hilltop maps: number of 4Xn binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, diagonal or antidiagonal neighbor in a random 0..3 4Xn array

1, 251, 4087, 65523, 1048363, 16773477, 268375113, 4294000777, 68704008397, 1099264075379, 17588224239783, 281411572315259, 4502584908606667, 72041354562688477, 1152661609402891673, 18442584732844711745

Offset

1,2

Comments

Row 4 of A218638

Links

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

Formula

Empirical: a(n) = 15*a(n-1) +14*a(n-2) +30*a(n-3) +27*a(n-4) +73*a(n-5) +96*a(n-6) +230*a(n-7) +167*a(n-8) -69*a(n-9) -116*a(n-10) -60*a(n-11) -13*a(n-12) -95*a(n-13) -254*a(n-14) -292*a(n-15) -120*a(n-16) for n>17

Example

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

Crossrefs

Sequence in context: A183840 A340636 A234929 * A090834 A078968 A365468

Adjacent sequences: A218636 A218637 A218638 * A218640 A218641 A218642

Keyword

nonn

Author

R. H. Hardin Nov 03 2012

Status

approved