A255658 Number of length n+6 0..3 arrays with at most two downsteps in every 6 consecutive neighbor pairs.

10320, 33042, 112196, 385738, 1324872, 4542671, 15269184, 50963540, 171784096, 583245999, 1978627688, 6707590534, 22709921860, 76722468914, 259180579024, 877068284264, 2969801621944, 10051964251804, 34016225117956

Offset: 1

Author

R. H. Hardin, Mar 01 2015

Keywords

• nonn

Comments

Column 6 of A255660

Examples

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

Links

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

Crossrefs

Cf. A255660

Formula

Empirical: a(n) = 4*a(n-1) -6*a(n-2) +20*a(n-3) -34*a(n-4) +24*a(n-5) +230*a(n-6) -552*a(n-7) +447*a(n-8) -4060*a(n-9) +6908*a(n-10) -2648*a(n-11) -10346*a(n-12) +26292*a(n-13) -21776*a(n-14) +185776*a(n-15) -406128*a(n-16) +326996*a(n-17) -196764*a(n-18) +82488*a(n-19) -13045*a(n-20) -115472*a(n-21) +108636*a(n-22) -29312*a(n-23) +73724*a(n-24) -12420*a(n-25) -41050*a(n-26) +38840*a(n-27) -21680*a(n-28) +3232*a(n-29) -12984*a(n-30) +13080*a(n-31) -4064*a(n-32) +320*a(n-34) +64*a(n-35)