A125316 Number of base 6 circular n-digit numbers with adjacent digits differing by 3 or less.

1, 6, 30, 138, 694, 3526, 18012, 92140, 471566, 2413794, 12356010, 63250314, 323779348, 1657433992, 8484446994, 43432107538, 222330112286, 1138113767838, 5826034724844, 29823627148788, 152667942902854

Offset: 0

Author

R. H. Hardin, Dec 28 2006

Keywords

• nonn
• base

Comments

[Empirical] a(base,n)=a(base-1,n)+A025012(n+1) for base>=3.int(n/2)+1.

Links

• OEIS Wiki, Number of base k circular n-digit numbers with adjacent digits differing by d or less

Formula

Conjectures from Colin Barker, Jun 04 2017: (Start)

G.f.: (1 - 3*x^2 - 16*x^3 + 3*x^4 + 8*x^5) / ((1 - x - x^2)*(1 - 5*x - x^2 + 2*x^3)).

a(n) = 6*a(n-1) - 3*a(n-2) - 8*a(n-3) + a(n-4) + 2*a(n-5) for n>5.

(End)