A218201 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..2 nX3 array

7, 59, 483, 3841, 30599, 243953, 1945103, 15508803, 123654745, 985923281, 7860958915, 62676962321, 499735676361, 3984490261291, 31769119935801, 253301405031061, 2019621630078545, 16102838151192633, 128391077151131153

Offset

1,1

Comments

Column 3 of A218206

Links

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

Formula

Empirical: a(n) = 7*a(n-1) +6*a(n-2) +12*a(n-3) +10*a(n-4) +48*a(n-5) +9*a(n-6) +5*a(n-7) +13*a(n-8) +11*a(n-9) -51*a(n-10) -59*a(n-11) -48*a(n-12) -38*a(n-13) +13*a(n-14) +39*a(n-15) +33*a(n-16) +15*a(n-17) +5*a(n-18) -5*a(n-19) -6*a(n-20) -2*a(n-21) +2*a(n-22) -a(n-24) -a(n-25)

Example

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

Crossrefs

Sequence in context: A236070 A059705 A359691 * A015568 A322667 A363105

Adjacent sequences: A218198 A218199 A218200 * A218202 A218203 A218204

Keyword

nonn

Author

R. H. Hardin Oct 23 2012

Status

approved