A198523 Number of nX3 0..4 arrays with values 0..4 introduced in row major order and each element equal to no more than two horizontal and vertical neighbors.

5, 193, 16714, 1877316, 222590953, 26670041125, 3201911378187, 384557171168810, 46189600128813487, 5547962760669962158, 666383179391895903794, 80041410904141273707361, 9614030302463648373863365

Offset: 1

Author

R. H. Hardin Oct 26 2011

Keywords

• nonn

Comments

Column 3 of A198528

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 140*a(n-1) -2296*a(n-2) -11502*a(n-3) +41183*a(n-4) +408760*a(n-5) +595837*a(n-6) -3718654*a(n-7) -13795951*a(n-8) -11064332*a(n-9) [phone]*a(n-10) [phone]*a(n-11) [phone]*a(n-12) -37607560*a(n-13) -266631136*a(n-14) -319325600*a(n-15) -322970496*a(n-16) -229207424*a(n-17) [phone]*a(n-18) [phone]*a(n-19) [phone]*a(n-20) [phone]*a(n-21) -8192000*a(n-22) -6356992*a(n-23) -786432*a(n-24) for n>25