A125469 Number of base 12 circular n-digit numbers with adjacent digits differing by 9 or less.

1, 12, 138, 1542, 17782, 205222, 2369460, 27358168, 315883982, 3647274798, 42112344498, 486239639898, 5614244249860, 64823465468332, 748467912775938, 8641997344805782, 99782658458533982, 1152115481155283262

Offset

0,2

Comments

[Empirical] a(base,n)=a(base-1,n)+F(9) for base>=9.int(n/2)+1 and F(d) is the largest coefficient in (1+x+...+x^(2d))^n.

Links

Table of n, a(n) for n=0..17.

Formula

G.f.: (1-3*x^2-52*x^3+3*x^4+32*x^5) / ((1-x-x^2)*(1-11*x-7*x^2+8*x^3)) (conjectured). - Colin Barker, Jul 17 2017

Prog

(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>9)+($[(i+1)mod N]`-$[i]`>9))

Crossrefs

Sequence in context: A059517 A243966 A097167 * A113366 A360203 A003379

Adjacent sequences: A125466 A125467 A125468 * A125470 A125471 A125472

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Status

approved