A269653 Number of length-n 0..5 arrays with no adjacent pair x,x+1 repeated.

6, 36, 216, 1291, 7686, 45590, 269472, 1587450, 9321628, 54569340, 318513432, 1853885152, 10761305560, 62304937944, 359833051280, 2073213227007, 11917692236634, 68357220234784, 391252708773072, 2234836878469971

Offset

1,1

Comments

Column 5 of A269656.

Links

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

Formula

Empirical: a(n) = 36*a(n-1) -570*a(n-2) +5244*a(n-3) -31353*a(n-4) +130248*a(n-5) -398332*a(n-6) +954000*a(n-7) -1897824*a(n-8) +3269288*a(n-9) -5011092*a(n-10) +6954336*a(n-11) -8842060*a(n-12) +10392360*a(n-13) -11368380*a(n-14) +11633264*a(n-15) -11177154*a(n-16) +10110960*a(n-17) -8629656*a(n-18) +6958872*a(n-19) -5305806*a(n-20) +3825752*a(n-21) -2608020*a(n-22) +1679472*a(n-23) -1020104*a(n-24) +583128*a(n-25) -312780*a(n-26) +156800*a(n-27) -73068*a(n-28) +31416*a(n-29) -12340*a(n-30) +4368*a(n-31) -1365*a(n-32) +364*a(n-33) -78*a(n-34) +12*a(n-35) -a(n-36)

Example

Some solutions for n=6
..0. .1. .3. .4. .4. .2. .5. .4. .2. .1. .3. .5. .4. .4. .1. .5
..3. .5. .3. .3. .3. .0. .1. .4. .0. .3. .4. .1. .4. .0. .4. .1
..3. .2. .4. .2. .0. .4. .4. .0. .5. .3. .0. .2. .2. .3. .0. .4
..0. .5. .3. .0. .2. .1. .4. .4. .0. .2. .2. .1. .5. .5. .2. .0
..1. .2. .5. .5. .3. .1. .4. .1. .5. .2. .5. .4. .0. .3. .1. .4
..4. .5. .2. .4. .4. .0. .4. .1. .5. .5. .3. .1. .2. .3. .5. .1

Crossrefs

Cf. A269656.

Sequence in context: A269687 A269491 A269773 * A250358 A126634 A216128

Adjacent sequences: A269650 A269651 A269652 * A269654 A269655 A269656

Keyword

nonn

Author

R. H. Hardin, Mar 02 2016

Status

approved