A218641 Hilltop maps: number of 6Xn binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, diagonal or antidiagonal neighbor in a random 0..3 6Xn array

1, 4001, 261505, 16773633, 1073490145, 68702054721, 4396923919617, 281403077821441, 18009795930773137, 1152626873213807201, 73768115566393606785, 4721159119167361543169, 302154165890141908970689

Offset

1,2

Comments

Row 6 of A218638

Links

Table of n, a(n) for n=1..13.

Example

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

Crossrefs

Sequence in context: A045262 A203088 A061700 * A092722 A034306 A228579

Adjacent sequences: A218638 A218639 A218640 * A218642 A218643 A218644

Keyword

nonn

Author

R. H. Hardin Nov 03 2012

Status

approved