A245946 Number of length n+3 0..4 arrays with some pair in every consecutive four terms totalling exactly 4.

453, 1889, 7769, 31465, 128649, 525041, 2141609, 8740385, 35666177, 145538749, 593901081, 2423511809, 9889552885, 40356071813, 164679993617, 672005573917, 2742236755101, 11190178304945, 45663487141625, 186337877072653

Offset: 1

Author

R. H. Hardin, Aug 08 2014

Keywords

• nonn

Comments

Column 4 of A245950.

Examples

			Some solutions for n=5
..0....4....2....1....1....0....0....0....1....0....1....2....2....1....3....4
..1....0....2....1....3....0....4....0....1....3....4....0....1....4....1....1
..4....3....0....0....4....3....0....4....3....1....3....1....3....3....0....3
..3....3....2....4....0....1....1....3....1....3....2....4....4....0....2....4
..1....1....3....0....0....1....2....3....2....1....1....4....0....0....3....2
..2....2....2....4....4....4....2....0....2....3....0....0....1....1....2....2
..2....0....2....4....2....0....0....4....3....3....3....0....0....3....1....4
..4....4....0....3....1....0....4....1....3....0....4....2....4....0....2....2
		

Links

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

Crossrefs

Cf. A245950.

Formula

Empirical: a(n) = 3*a(n-1) +5*a(n-2) +3*a(n-3) -10*a(n-4) -37*a(n-5) -48*a(n-6) -37*a(n-7) +83*a(n-8) +143*a(n-9) +5*a(n-10) -11*a(n-11) -41*a(n-12) -10*a(n-13) -2*a(n-14) +3*a(n-15).