login
A125319
Number of base 9 circular n-digit numbers with adjacent digits differing by 3 or less.
0
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
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
KEYWORD
nonn,base
AUTHOR
R. H. Hardin, Dec 28 2006
STATUS
approved