A125398 Number of base 10 circular n-digit numbers with adjacent digits differing by 6 or less.

1, 10, 88, 724, 6412, 57120, 510214, 4559754, 40756276, 364302976, 3256378378, 29107705802, 260184449794, 2325705707374, 20788741351382, 185823928401414, 1661020831456212, 14847335474122436, 132715596660687976

Offset

0,2

Comments

[Empirical] a(base,n)=a(base-1,n)+F(6) for base>=6.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..18.

Formula

G.f.: (1 - 6*x^2 - 64*x^3 + 15*x^4 + 88*x^5 - 5*x^6 - 24*x^7) / ((1 - 2*x - x^2 + x^3)*(1 - 8*x - 9*x^2 + 5*x^3 + 4*x^4)) (conjectured). - Colin Barker, Jun 01 2017

Prog

(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>6)+($[(i+1)mod N]`-$[i]`>6))

Crossrefs

Sequence in context: A136864 A099789 A185060 * A273585 A165148 A287828

Adjacent sequences: A125395 A125396 A125397 * A125399 A125400 A125401

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Status

approved