A218191 - OEIS

A218191

Hilltop maps: number of nX3 binary arrays indicating the locations of corresponding elements not exceeded by any horizontal or vertical neighbor in a random 0..3 nX3 array.

7, 63, 507, 4067, 32529, 260205, 2081511, 16651157, 133202247, 1065561647, 8524042607, 68188735807, 545481047051, 4363617673705, 34907095864651, 279242003501369, 2233817926927103, 17869598656697015, 142949231583388401

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Column 3 of A218196

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..202

FORMULA

Empirical: a(n) = 7*a(n-1) +7*a(n-2) +7*a(n-3) +6*a(n-4) +12*a(n-5) +10*a(n-6) +48*a(n-7) +9*a(n-8) +9*a(n-9) +9*a(n-10) +5*a(n-11) +13*a(n-12) +11*a(n-13) -52*a(n-14) -64*a(n-15) -63*a(n-16) -59*a(n-17) -48*a(n-18) -38*a(n-19) +13*a(n-20) +41*a(n-21) +48*a(n-22) +46*a(n-23) +33*a(n-24) +15*a(n-25) +5*a(n-26) -5*a(n-27) -7*a(n-28) -7*a(n-29) -6*a(n-30) -2*a(n-31) +2*a(n-32) -a(n-34) -a(n-35) -a(n-36) -a(n-37)

EXAMPLE

Some solutions for n=3

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

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

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

CROSSREFS

Sequence in context: A219058 A182603 A320073 * A218367 A218314 A218633

Adjacent sequences: A218188 A218189 A218190 * A218192 A218193 A218194

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 23 2012

STATUS

approved