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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
1
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
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
KEYWORD
nonn
AUTHOR
R. H. Hardin Oct 23 2012
STATUS
approved