A302821 Number of 3Xn 0..1 arrays with every element equal to 0, 1, 2, 4 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

4, 25, 75, 220, 731, 2419, 7900, 25645, 83685, 273504, 893195, 2915411, 9518108, 31079021, 101478805, 331335348, 1081839931, 3532345439, 11533574036, 37658571753, 122959986781, 401480186136, 1310884882811, 4280209057195

Offset

1,1

Comments

Row 3 of A302820.

Links

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

Formula

Empirical: a(n) = 6*a(n-1) -9*a(n-2) +2*a(n-4) -18*a(n-5) +37*a(n-6) +34*a(n-7) +5*a(n-8) -52*a(n-9) -118*a(n-10) -24*a(n-11) +190*a(n-12) +10*a(n-13) -68*a(n-14) +12*a(n-15) for n>16

Example

Some solutions for n=5
..0..1..1..1..1. .0..1..1..1..0. .0..0..0..0..0. .0..1..0..0..0
..0..1..0..1..0. .0..1..0..1..0. .0..0..0..0..0. .0..0..1..1..1
..0..1..0..0..0. .0..1..1..1..0. .1..1..0..1..1. .1..1..0..1..0

Crossrefs

Cf. A302820.

Sequence in context: A298282 A077205 A180569 * A125309 A273361 A266126

Adjacent sequences: A302818 A302819 A302820 * A302822 A302823 A302824

Keyword

nonn

Author

R. H. Hardin, Apr 13 2018

Status

approved