A126398 Number of base 11 n-digit numbers with adjacent digits differing by two or less.

1, 11, 49, 225, 1043, 4861, 22723, 106401, 498703, 2338691, 10970731, 51472161, 241518759, 1133320429, 5318237121, 24956866179, 117116084385, 549598276829, 2579143380799, 12103370927679, 56798597444915, 266544122924215

Offset: 0

Author

R. H. Hardin, Dec 28 2006

Keywords

• nonn
• base

Comments

[Empirical] a(base,n)=a(base-1,n)+5^(n-1) for base>=2n-1; a(base,n)=a(base-1,n)+5^(n-1)-2 when base=2n-2.

Crossrefs

Cf. Base 11 differing by one or less A126365.

Formula

G.f.: (1+4*x-19*x^2-8*x^3+19*x^4+x^5-2*x^6) / (1-7*x+9*x^2+11*x^3-11*x^4-2*x^5+x^6) (conjectured). - Colin Barker, Jul 17 2017