A209605 Number of nX3 1..2 arrays with every element value z a city block distance of exactly z from another element value z

1, 11, 125, 955, 6218, 39667, 260861, 1735169, 11583064, 77177265, 513065936, 3410493065, 22677826673, 150811145600, 1002946696389, 6669821781399, 44354925109263, 294963866816031, 1961539878519870, 13044456725291363

Offset

1,2

Comments

Column 3 of A209610

Links

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

Formula

Empirical: a(n) = 7*a(n-1) -9*a(n-2) +46*a(n-3) -73*a(n-4) +423*a(n-5) +108*a(n-6) -1047*a(n-7) -1114*a(n-8) +2806*a(n-9) +8923*a(n-10) -15196*a(n-11) -13785*a(n-12) +9268*a(n-13) +22926*a(n-14) +8592*a(n-15) -37983*a(n-16) +41260*a(n-17) -10256*a(n-18) -32347*a(n-19) +16513*a(n-20) -38656*a(n-21) +31395*a(n-22) +26726*a(n-23) -53598*a(n-24) +34102*a(n-25) +8752*a(n-26) -16658*a(n-27) -1894*a(n-28) -6260*a(n-29) +13974*a(n-30) -3006*a(n-31) -9706*a(n-32) +9126*a(n-33) -1510*a(n-34) -1244*a(n-35) +380*a(n-36) +232*a(n-37) +12*a(n-38) +16*a(n-39) -16*a(n-40) for n>41

Example

Some solutions for n=4
..1..1..2....1..1..1....1..1..2....1..1..2....2..1..2....2..2..1....2..1..2
..2..1..1....2..2..2....2..1..2....1..2..2....2..1..2....2..2..1....1..1..1
..1..2..2....1..1..2....2..1..2....1..2..2....2..1..2....2..1..2....2..1..1
..1..1..1....2..2..2....1..1..1....1..1..2....1..1..1....2..1..1....2..2..2

Crossrefs

Sequence in context: A224816 A015594 A376146 * A362675 A282755 A242523

Adjacent sequences: A209602 A209603 A209604 * A209606 A209607 A209608

Keyword

nonn

Author

R. H. Hardin Mar 10 2012

Status

approved