A231286 Number of 3Xn 0..3 arrays x(i,j) with each element horizontally or antidiagonally next to at least one element with value (x(i,j)+1) mod 4, and upper left element zero

0, 0, 8, 76, 834, 9488, 105962, 1179364, 13125298, 146097624, 1626238194, 18101813556, 201493039018, 2242839951880, 24965287273578, 277891238282180, 3093236609372642, 34431142194463224, 383256667023706306

Offset

1,3

Comments

Row 3 of A231285

Links

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

Formula

Empirical: a(n) = 26*a(n-1) -267*a(n-2) +1560*a(n-3) -6087*a(n-4) +17438*a(n-5) -38845*a(n-6) +70000*a(n-7) -108952*a(n-8) +161144*a(n-9) -214028*a(n-10) +150344*a(n-11) +187284*a(n-12) -587360*a(n-13) +482160*a(n-14) +11936*a(n-15) -126224*a(n-16) -26496*a(n-17) -29888*a(n-18) +19968*a(n-19) for n>21

Example

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

Crossrefs

Sequence in context: A247744 A144851 A233827 * A251927 A024281 A232087

Adjacent sequences: A231283 A231284 A231285 * A231287 A231288 A231289

Keyword

nonn

Author

R. H. Hardin, Nov 06 2013

Status

approved