A218368 Hilltop maps: number of nX4 binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, vertical or antidiagonal neighbor in a random 0..3 nX4 array

15, 253, 4081, 65409, 1046529, 16744435, 267910753, 4286570153, 68585092161, 1097360991969, 17557768153359, 280924166963785, 4494784695580905, 71916523515869329, 1150663870439327625, 18410613833999482211

Offset

1,1

Comments

Column 4 of A218372

Links

R. H. Hardin, Table of n, a(n) for n = 1..119

Formula

Empirical: a(n) = 15*a(n-1) +15*a(n-2) +15*a(n-3) +15*a(n-4) +13*a(n-5) +33*a(n-6) +107*a(n-7) +107*a(n-8) +107*a(n-9) +106*a(n-10) +110*a(n-11) +142*a(n-12) +232*a(n-13) +175*a(n-14) +175*a(n-15) +175*a(n-16) +169*a(n-17) +161*a(n-18) +115*a(n-19) -53*a(n-20) -53*a(n-21) -53*a(n-22) -51*a(n-23) -16*a(n-24) +56*a(n-25) -85*a(n-26) -43*a(n-27) -43*a(n-28) -43*a(n-29) -39*a(n-30) +19*a(n-31) -5*a(n-32) -7*a(n-33) -7*a(n-34) -7*a(n-35) -8*a(n-36) +2*a(n-37) -6*a(n-38) -2*a(n-39) -3*a(n-40) -3*a(n-41) -3*a(n-42) -a(n-43) -a(n-44) +a(n-45) +a(n-46) +a(n-47) +a(n-48) +a(n-49)

Example

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

Crossrefs

Sequence in context: A370317 A116508 A055659 * A123816 A273921 A182607

Adjacent sequences: A218365 A218366 A218367 * A218369 A218370 A218371

Keyword

nonn

Author

R. H. Hardin Oct 27 2012

Status

approved