A255657 Number of length n+5 0..3 arrays with at most two downsteps in every 5 consecutive neighbor pairs.

3340, 11752, 42653, 155144, 564600, 2036844, 7323894, 26452984, 95690028, 345980784, 1250385422, 4516046380, 16313317592, 58952879320, 213036643465, 769783313248, 2781411265212, 10049660711008, 36312457046956, 131210437887132, 474105380419912, 1713085295392596

Offset: 1

Author

R. H. Hardin, Mar 01 2015

Keywords

• nonn
• changed

Examples

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

Links

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

Crossrefs

Column 5 of A255660.

Formula

Empirical: a(n) = 4*a(n-1) -6*a(n-2) +20*a(n-3) -34*a(n-4) +148*a(n-5) -266*a(n-6) +192*a(n-7) -622*a(n-8) +1120*a(n-9) -3788*a(n-10) +6836*a(n-11) -5078*a(n-12) +3368*a(n-13) -1500*a(n-14) +1172*a(n-15) -603*a(n-16) +152*a(n-17) -376*a(n-18) +272*a(n-19) -156*a(n-20) +68*a(n-21) -10*a(n-22) +a(n-24).