A231033 Number of nX4 0..2 arrays x(i,j) with each element horizontally, diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 3 and at least one element with value (x(i,j)-1) mod 3, and upper left element zero

0, 4, 72, 1344, 20250, 375620, 6620496, 114765278, 2040092280, 36070020410, 636310267444, 11259982687398, 199143247111778, 3520995724132754, 62277455575772414, 1101469857027050006, 19480402257921072406

Offset

1,2

Comments

Column 4 of A231037

Links

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

Formula

Empirical: a(n) = 21*a(n-1) -43*a(n-2) +423*a(n-3) -14174*a(n-4) +21017*a(n-5) +191825*a(n-6) +94369*a(n-7) -613129*a(n-8) -1029890*a(n-9) -1078481*a(n-10) +5497567*a(n-11) -710152*a(n-12) +3590349*a(n-13) -22983986*a(n-14) +18281674*a(n-15) -13233964*a(n-16) -6664969*a(n-17) +43490862*a(n-18) -17505341*a(n-19) +66788832*a(n-20) -73478356*a(n-21) +1062316*a(n-22) +30795118*a(n-23) -61983450*a(n-24) -3817913*a(n-25) +638020*a(n-26) +8955793*a(n-27) -296821*a(n-28) +286492*a(n-29) +1894901*a(n-30) -851834*a(n-31) +412801*a(n-32) -183119*a(n-33) -7194*a(n-34) +2736*a(n-35) -138*a(n-36) -96*a(n-37)

Example

Some solutions for n=3
..0..1..0..1....0..2..2..0....0..1..2..0....0..2..2..0....0..2..2..0
..1..2..2..2....0..1..1..0....2..2..1..1....2..1..1..0....2..1..1..1
..1..0..1..0....0..2..0..2....1..0..0..2....2..0..2..0....2..0..0..2

Crossrefs

Sequence in context: A060645 A363987 A203073 * A307358 A201976 A328426

Adjacent sequences: A231030 A231031 A231032 * A231034 A231035 A231036

Keyword

nonn

Author

R. H. Hardin, Nov 03 2013

Status

approved