A240286 Number of 3Xn 0..3 arrays with no element equal to one plus the sum of elements to its left or two plus the sum of the elements above it or zero plus the sum of the elements diagonally to its northwest, modulo 4.

3, 19, 80, 570, 2574, 20764, 97348, 802835, 3797188, 31467286, 149131302, 1237084277, 5865347475, 48665192186, 230756350987, 1914691579848, 9079103009997, 75334276334445, 357222415759008, 2964076274068268

Offset: 1

Author

R. H. Hardin, Apr 03 2014

Keywords

• nonn

Comments

Row 3 of A240284

Examples

			Some solutions for n=4
..3..3..1..3....3..1..3..1....3..3..1..1....3..1..3..1....3..3..1..3
..2..0..1..3....3..2..3..2....2..0..0..2....3..1..2..0....3..2..0..3
..2..0..1..2....2..2..3..2....2..0..0..0....3..1..2..0....3..1..2..2
		

Links

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

Formula

Empirical: a(n) = 63*a(n-2) -1109*a(n-4) +7143*a(n-6) -395*a(n-8) -201246*a(n-10) +762860*a(n-12) +347011*a(n-14) -7366154*a(n-16) [phone]*a(n-18) +3758987*a(n-20) [phone]*a(n-22) -126415852*a(n-24) [phone]*a(n-26) -65238786*a(n-28) -59211883*a(n-30) -114625640*a(n-32) [phone]*a(n-34) -342073760*a(n-36) [phone]*a(n-38) [phone]*a(n-40) -110895680*a(n-42) [phone]*a(n-44) +1175136*a(n-46) +390464*a(n-48) for n>51