A125425 Number of base 13 circular n-digit numbers with adjacent digits differing by 7 or less.

1, 13, 139, 1357, 14591, 158703, 1735537, 19008065, 208287079, 2282738371, 25019137619, 274217831395, 3005531920793, 32941830915539, 361055827137585, 3957318988935327, 43373831073632999, 475394897638619787

Offset

0,2

Comments

[Empirical] a(base,n)=a(base-1,n)+F(7) for base>=7.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.

Prog

(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>7)+($[(i+1)mod N]`-$[i]`>7))

Crossrefs

Sequence in context: A142896 A193700 A241631 * A016145 A351812 A300694

Adjacent sequences: A125422 A125423 A125424 * A125426 A125427 A125428

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Status

approved