A255621 Number of length n+7 0..2 arrays with at most two downsteps in every 7 consecutive neighbor pairs

3834, 9186, 23298, 60390, 156563, 405687, 1047141, 2656032, 6682971, 16925280, 43249522, 110788455, 283416570, 724728391, 1851244551, 4719321474, 12020625692, 30651759318, 78266507064, 199890070327, 510335125536

Offset

1,1

Comments

Column 7 of A255622

Links

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

Formula

Empirical: a(n) = 3*a(n-1) -3*a(n-2) +a(n-3) +12*a(n-4) -18*a(n-5) +7*a(n-6) +153*a(n-7) -237*a(n-8) +95*a(n-9) -885*a(n-11) +1087*a(n-12) -123*a(n-13) -6870*a(n-14) +8984*a(n-15) -1401*a(n-16) -1260*a(n-17) +11772*a(n-18) -16266*a(n-19) +6696*a(n-20) +69471*a(n-21) -114183*a(n-22) +47448*a(n-23) -100*a(n-24) -17955*a(n-25) +5628*a(n-26) -700*a(n-27) -2565*a(n-28) +804*a(n-29) -100*a(n-30)

Example

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

Crossrefs

Cf. A255622

Sequence in context: A234668 A259522 A209894 * A212228 A231416 A151564

Adjacent sequences: A255618 A255619 A255620 * A255622 A255623 A255624

Keyword

nonn

Author

R. H. Hardin, Feb 28 2015

Status

approved