A269639 Number of length-n 0..7 arrays with no repeated value differing from the previous repeated value by other than plus two or minus 1.

8, 64, 504, 3933, 30444, 234080, 1789528, 13613507, 103118640, 778158768, 5852649288, 43888314093, 328240366020, 2449045039552, 18233174801384, 135479775215950, 1004866303875264, 7440970750295140, 55016954785772120

Offset

1,1

Comments

Column 7 of A269640.

Links

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

Formula

Empirical: a(n) = 56*a(n-1) -1344*a(n-2) +17752*a(n-3) -135716*a(n-4) +545496*a(n-5) -463786*a(n-6) -4675564*a(n-7) +12243456*a(n-8) +21822328*a(n-9) -72836660*a(n-10) -123804240*a(n-11) +151424498*a(n-12) +520495760*a(n-13) +515921322*a(n-14) +232811740*a(n-15) +41061559*a(n-16)

Example

Some solutions for n=5
..1. .7. .0. .1. .0. .1. .7. .3. .2. .3. .6. .1. .6. .3. .1. .3
..5. .1. .3. .7. .7. .0. .6. .1. .0. .5. .5. .0. .4. .0. .0. .0
..7. .2. .7. .0. .4. .0. .7. .2. .6. .2. .3. .2. .2. .3. .5. .0
..5. .6. .6. .2. .5. .1. .3. .2. .3. .5. .5. .6. .3. .6. .2. .5
..1. .2. .4. .3. .4. .4. .6. .5. .5. .3. .2. .4. .4. .6. .5. .7

Crossrefs

Cf. A269640.

Sequence in context: A267470 A227591 A268943 * A269536 A269677 A269408

Adjacent sequences: A269636 A269637 A269638 * A269640 A269641 A269642

Keyword

nonn

Author

R. H. Hardin, Mar 02 2016

Status

approved