A125447 Number of base 12 circular n-digit numbers with adjacent digits differing by 8 or less.

1, 12, 132, 1380, 15260, 169252, 1879782, 20881502, 231972500, 2577002988, 28628206202, 318033966218, 3533075401202, 39249335918974, 436025331971998, 4843854954088810, 53810935050499732, 597791791563925916

Offset

0,2

Comments

[Empirical] a(base,n)=a(base-1,n)+F(8) for base>=8.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.: (1-6*x^2-88*x^3+15*x^4+128*x^5-5*x^6-36*x^7) / ((1-2*x-x^2+x^3)*(1-10*x-13*x^2+7*x^3+6*x^4)) (conjectured). - Colin Barker, Jul 17 2017

Prog

(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>8)+($[(i+1)mod N]`-$[i]`>8))

Crossrefs

Sequence in context: A334334 A119237 A038729 * A162767 A003495 A324947

Adjacent sequences: A125444 A125445 A125446 * A125448 A125449 A125450

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Status

approved