A218634 - OEIS

A218634

Hilltop maps: number of nX4 binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, diagonal or antidiagonal neighbor in a random 0..3 nX4 array

15, 255, 4095, 65523, 1048353, 16773633, 268378101, 4294049121, 68704778799, 1099276346403, 17588419711983, 281414686103379, 4502634509040741, 72042144646840065, 1152674194384463589, 18442785190711981653

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OFFSET

1,1

COMMENTS

Column 4 of A218638

LINKS

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

FORMULA

Empirical: a(n) = 15*a(n-1) +15*a(n-2) +15*a(n-3) +15*a(n-4) +15*a(n-5) +12*a(n-6) +36*a(n-7) -27*a(n-8) -27*a(n-9) -27*a(n-10) -27*a(n-11) -27*a(n-12) -27*a(n-13)

EXAMPLE

Some solutions for n=3

..1..0..1..0....0..1..0..1....1..1..1..0....1..1..1..1....1..0..0..1

..0..0..0..0....0..0..1..0....0..1..1..0....1..1..0..0....1..0..0..0

..1..1..1..1....1..1..0..0....1..0..0..1....0..1..0..0....1..1..0..1

CROSSREFS

Sequence in context: A273921 A182607 A218284 * A218238 A015691 A145562

Adjacent sequences: A218631 A218632 A218633 * A218635 A218636 A218637

KEYWORD

nonn

AUTHOR

R. H. Hardin Nov 03 2012

STATUS

approved