A268953 Number of length-n 0..5 arrays with no repeated value equal to the previous repeated value, with new values introduced in sequential order.

1, 2, 4, 12, 40, 154, 655, 3045, 15124, 78930, 426289, 2355975, 13216982, 74856340, 426491859, 2438853865, 13977348104, 80210943670, 460646222293, 2646524858907, 15207848530170, 87395420173144, 502235483752631, 2886069610014893

Offset

1,2

Comments

Column 5 of A268956.

Links

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

Formula

Empirical: a(n) = 18*a(n-1) -110*a(n-2) +170*a(n-3) +801*a(n-4) -2920*a(n-5) -662*a(n-6) +12700*a(n-7) -6980*a(n-8) -22928*a(n-9) +19192*a(n-10) +15120*a(n-11) -14400*a(n-12) for n>14

Example

Some solutions for n=8
..0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0. .0
..1. .1. .1. .1. .0. .1. .1. .0. .1. .1. .1. .1. .1. .1. .1. .0
..0. .2. .0. .0. .1. .2. .0. .1. .2. .1. .1. .2. .1. .0. .2. .1
..1. .3. .0. .2. .0. .0. .2. .2. .0. .2. .2. .2. .2. .1. .3. .2
..1. .3. .2. .0. .2. .2. .1. .2. .3. .0. .3. .3. .1. .1. .4. .1
..2. .4. .1. .1. .2. .3. .0. .3. .3. .3. .1. .1. .0. .0. .4. .0
..2. .0. .3. .0. .3. .2. .0. .1. .1. .4. .3. .2. .3. .2. .1. .3
..3. .4. .0. .0. .1. .1. .1. .0. .0. .3. .1. .0. .1. .0. .1. .0

Crossrefs

Cf. A268956.

Sequence in context: A268952 A215072 A326513 * A268954 A268955 A268010

Adjacent sequences: A268950 A268951 A268952 * A268954 A268955 A268956

Keyword

nonn

Author

R. H. Hardin, Feb 16 2016

Status

approved