A125317 Number of base 7 circular n-digit numbers with adjacent digits differing by 3 or less.

1, 7, 37, 175, 925, 4977, 27067, 147777, 808165, 4422703, 24210127, 132542813, 725664307, 3973047319, 21752799623, 119098967235, 652080798837, 3570220727531, 19547391880633, 107024353337437, 585971402810715

Offset

0,2

Comments

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

Links

Table of n, a(n) for n=0..20.

Formula

G.f.: (1 - 6*x^2 - 28*x^3 + 15*x^4 + 28*x^5 - 5*x^6 - 6*x^7) / ((1 - 2*x - x^2 + x^3)*(1 - 5*x - 3*x^2 + 2*x^3 + x^4)) (conjectured). - Colin Barker, Jun 03 2017

Prog

(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>3)+($[(i+1)mod N]`-$[i]`>3))

Crossrefs

Sequence in context: A005061 A099454 A177414 * A006419 A277178 A026673

Adjacent sequences: A125314 A125315 A125316 * A125318 A125319 A125320

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Status

approved