A231026 Number of nX3 0..2 arrays x(i,j) with each element horizontally, vertically 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, 12, 60, 1074, 12400, 162288, 2049324, 26149710, 332659424, 4235875140, 53922195170, 686478044994, 8739276731656, 111257016629792, 1416375531056864, 18031410076232628, 229551897159731062, 2922349174918753464

Offset

1,2

Comments

Column 3 of A231031

Links

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

Formula

Empirical: a(n) = 12*a(n-1) +24*a(n-2) -198*a(n-3) +143*a(n-4) -39*a(n-5) -1072*a(n-6) +15046*a(n-7) -50039*a(n-8) -76233*a(n-9) +310401*a(n-10) -79074*a(n-11) -282050*a(n-12) +99013*a(n-13) +127303*a(n-14) -86657*a(n-15) +1974*a(n-16) +55618*a(n-17) -23205*a(n-18) -15363*a(n-19) +9601*a(n-20) -2560*a(n-21) -2599*a(n-22) +1807*a(n-23) +98*a(n-24) -123*a(n-25) +124*a(n-26) -a(n-27) -14*a(n-28)

Example

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

Crossrefs

Sequence in context: A108096 A056388 A056378 * A333969 A076504 A232700

Adjacent sequences: A231023 A231024 A231025 * A231027 A231028 A231029

Keyword

nonn

Author

R. H. Hardin, Nov 03 2013

Status

approved