A221576 Number of 0..n arrays of length 6 with each element differing from at least one neighbor by something other than 1.

10, 141, 1210, 5913, 20944, 59705, 145800, 317233, 631328, 1170369, 2047960, 3416105, 5473008, 8471593, 12728744, 18635265, 26666560, 37394033, 51497208, 69776569, 93167120, 122752665, 159780808, 205678673, 262069344, 330789025

Offset

1,1

Comments

Row 6 of A221573.

Links

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

Formula

Empirical: a(n) = 1*n^6 + 2*n^5 - 5*n^4 + 24*n^3 - 41*n^2 + 50*n - 31 for n>3.

Conjectures from Colin Barker, Aug 08 2018: (Start)

G.f.: x*(10 + 71*x + 433*x^2 + 54*x^3 + 378*x^4 - 355*x^5 + 193*x^6 - 80*x^7 + 18*x^8 - 2*x^9) / (1 - x)^7.

a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>10.

(End)

Example

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

Crossrefs

Cf. A221573.

Sequence in context: A319578 A051618 A295034 * A254834 A093470 A093471

Adjacent sequences: A221573 A221574 A221575 * A221577 A221578 A221579

Keyword

nonn

Author

R. H. Hardin, Jan 20 2013

Status

approved