A125319 Number of base 9 circular n-digit numbers with adjacent digits differing by 3 or less.

1, 9, 51, 249, 1387, 7879, 45663, 267367, 1575395, 9316455, 55211811, 327600447, 1945195699, 11554693471, 68652279747, 407952680479, 2424365629955, 14408066169471, 85629681584835, 508919764066431, 3024669695471107

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 - x - 14*x^2 - 36*x^3 + 138*x^4 - 58*x^5 - 52*x^6 + 28*x^7) / ((1 - x)*(1 + x)*(1 - 4*x + 2*x^2)*(1 - 6*x + 2*x^3)) (conjectured). - Colin Barker, Jun 02 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: A278135 A097789 A080624 * A080621 A027218 A155617

Adjacent sequences: A125316 A125317 A125318 * A125320 A125321 A125322

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Status

approved