A125346 Number of base 9 circular n-digit numbers with adjacent digits differing by 4 or less.

1, 9, 61, 369, 2501, 17259, 120367, 842739, 5910189, 41476599, 291156071, 2044081081, 14351282807, 100760813695, 707450453645, 4967087326989, 34874511797933, 244858234557953, 1719180148930309, 12070578961004535

Offset

0,2

Comments

[Empirical] a(base,n)=a(base-1,n)+A025014(n+1) for base>=4.int(n/2)+1

Links

Table of n, a(n) for n=0..19.

Formula

G.f.: (1 - 10*x^2 - 60*x^3 + 45*x^4 + 108*x^5 - 35*x^6 - 54*x^7 + 7*x^8 + 8*x^9) / ((1 + x)*(1 - 3*x + x^3)*(1 - 7*x - x^2 + 6*x^3 - x^5)) (conjectured). - Colin Barker, Jun 02 2017

Prog

(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>4)+($[(i+1)mod N]`-$[i]`>4))

Crossrefs

Cf. A025014.

Sequence in context: A201084 A305783 A005060 * A190666 A016200 A001454

Adjacent sequences: A125343 A125344 A125345 * A125347 A125348 A125349

Keyword

nonn,base

Author

R. H. Hardin, Dec 28 2006

Status

approved