A230827 Number of nX4 0..3 arrays x(i,j) with each element horizontally, vertically or antidiagonally next to at least one element with value (x(i,j)+1) mod 4 and at least one element with value (x(i,j)-1) mod 4, no adjacent elements equal, and upper left element zero

0, 6, 10, 62, 176, 734, 3034, 12962, 55806, 241462, 1047244, 4548392, 19770622, 85983476, 374071534, 1627718734, 7083554700, 30828250368, 134171670508, 583957263660, 2541594468334, 11062020222648, 48146469919922

Offset

1,2

Comments

Column 4 of A230831

Links

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

Formula

Empirical: a(n) = 20*a(n-1) -174*a(n-2) +856*a(n-3) -2543*a(n-4) +4242*a(n-5) -1758*a(n-6) -8383*a(n-7) +18429*a(n-8) -9998*a(n-9) -19479*a(n-10) +35858*a(n-11) -3796*a(n-12) -44630*a(n-13) +26155*a(n-14) +46885*a(n-15) -36285*a(n-16) -52603*a(n-17) +27731*a(n-18) +62520*a(n-19) -8480*a(n-20) -68927*a(n-21) +7432*a(n-22) +63362*a(n-23) -4203*a(n-24) -57711*a(n-25) -41467*a(n-26) +16827*a(n-27) +61539*a(n-28) +68672*a(n-29) +13282*a(n-30) -105380*a(n-31) -115207*a(n-32) +42704*a(n-33) +133454*a(n-34) +42704*a(n-35) -68204*a(n-36) -61800*a(n-37) +6457*a(n-38) +32367*a(n-39) +12804*a(n-40) -4313*a(n-41) -5391*a(n-42) -1966*a(n-43) -339*a(n-44) -26*a(n-45) -a(n-46) for n>51

Example

Some solutions for n=4
..0..1..0..1....0..3..2..3....0..1..3..2....0..1..2..0....0..1..2..0
..3..2..3..2....1..0..1..0....3..2..0..1....3..0..3..1....3..0..3..1
..0..1..0..1....2..3..2..3....0..1..3..2....2..1..2..3....2..1..2..3
..3..2..3..2....1..0..1..0....3..2..0..1....0..3..1..0....3..0..1..0

Crossrefs

Sequence in context: A136849 A136847 A250106 * A372070 A111484 A119041

Adjacent sequences: A230824 A230825 A230826 * A230828 A230829 A230830

Keyword

nonn

Author

R. H. Hardin, Oct 30 2013

Status

approved