A269204 Number of 4Xn 0..3 arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling three no more than once.

256, 15540, 471492, 15289548, 463790340, 13753913556, 399104835612, 11402099212308, 321701652077076, 8985658235129964, 248904744378939924, 6846738391062856596, 187219797100389992412, 5093241917191742737620

Offset: 1

Author

R. H. Hardin, Feb 20 2016

Keywords

• nonn

Comments

Row 4 of A269201.

Examples

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

Links

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

Crossrefs

Cf. A269201.

Formula

Empirical: a(n) = 48*a(n-1) -424*a(n-2) -5664*a(n-3) +40624*a(n-4) +218356*a(n-5) -1300662*a(n-6) -2980700*a(n-7) [phone]*a(n-8) +2629424*a(n-9) -96328452*a(n-10) [phone]*a(n-11) -10936481*a(n-12) -91456900*a(n-13) [phone]*a(n-14) +9975760*a(n-15) -14279120*a(n-16) +2348160*a(n-17) +465152*a(n-18) -79872*a(n-19) -9216*a(n-20)