A209470 Number of nX2 0..2 arrays with every element value z a city block distance of exactly z from another element value z

2, 13, 93, 635, 4357, 27989, 175599, 1097149, 6898767, 43661399, 277088463, 1758632349, 11151301399, 70656266965, 447562532731, 2835123056355, 17961560639715, 113803029648973, 721065928522417, 4568695947257233

Offset

1,1

Comments

Column 2 of A209476

Links

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

Formula

Empirical: a(n) = 7*a(n-1) -7*a(n-2) -4*a(n-3) +66*a(n-4) +304*a(n-5) +718*a(n-6) +1784*a(n-7) -1409*a(n-8) -3322*a(n-9) -13020*a(n-10) -15966*a(n-11) -18299*a(n-12) -14110*a(n-13) -25099*a(n-14) -14477*a(n-15) -28326*a(n-16) +8287*a(n-17) -13319*a(n-18) +13953*a(n-19) -8803*a(n-20) +22525*a(n-21) +4118*a(n-22) +2705*a(n-23) +3161*a(n-24) +4528*a(n-25) -280*a(n-26) -1198*a(n-27) -384*a(n-28) -1636*a(n-29) -200*a(n-30) +80*a(n-31) +32*a(n-32) +128*a(n-33)

Example

Some solutions for n=5
..2..2....1..1....1..1....2..0....0..0....0..2....0..2....1..1....1..1....1..0
..2..1....2..2....1..1....2..2....2..0....2..2....0..2....2..1....2..0....1..1
..2..1....1..1....1..1....2..2....0..0....2..0....2..2....0..2....2..2....0..1
..2..1....2..2....1..1....0..2....2..0....1..1....1..1....0..0....0..2....1..1
..0..0....0..0....1..1....2..0....1..1....0..0....1..1....1..1....2..0....0..1

Crossrefs

Sequence in context: A367785 A199489 A300764 * A140636 A369413 A282724

Adjacent sequences: A209467 A209468 A209469 * A209471 A209472 A209473

Keyword

nonn

Author

R. H. Hardin Mar 09 2012

Status

approved