A297509 Number of 4Xn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1 or 2 neighboring 1s.

1, 87, 531, 2281, 23348, 191192, 1247716, 9450219, 74086027, 542295341, 4014135733, 30366147431, 226985241429, 1690164545942, 12658565659102, 94748613114792, 707806468257951, 5292426347783239, 39588593164337549

Offset: 1

Author

R. H. Hardin, Dec 31 2017

Keywords

• nonn

Comments

Row 4 of A297506.

Examples

			Some solutions for n=6
..1..1..0..0..1..0. .0..0..0..0..0..1. .1..1..1..1..0..0. .0..0..0..0..0..1
..0..0..0..1..1..0. .0..0..0..0..1..0. .0..0..0..0..0..0. .0..1..1..0..1..0
..0..0..0..0..0..1. .0..0..0..0..1..0. .0..0..0..1..0..0. .0..0..0..0..0..0
..0..1..1..0..1..0. .0..0..0..1..0..1. .0..1..1..0..1..0. .0..1..1..0..1..1
		

Links

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

Crossrefs

Cf. A297506.

Formula

Empirical: a(n) = 6*a(n-1) +a(n-2) +122*a(n-3) -209*a(n-4) -1087*a(n-5) -354*a(n-6) +4059*a(n-7) +1206*a(n-8) +3818*a(n-9) +692*a(n-10) -11767*a(n-11) -6075*a(n-12) -2835*a(n-13) -949*a(n-14) +8451*a(n-15) +6295*a(n-16) -636*a(n-17) +2500*a(n-18) -3242*a(n-19) -1428*a(n-20) +742*a(n-21) +74*a(n-22) -24*a(n-23) +2*a(n-24)