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A125468 Number of base 11 circular n-digit numbers with adjacent digits differing by 9 or less. 0
1, 11, 119, 1271, 13763, 149051, 1614359, 17485031, 189379523, 2051160491, 22216020599, 240620650391, 2606150689283, 28227092746331, 305726283666839, 3311306671385351, 35864603266855043, 388447792711018571 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

[Empirical] a(base,n)=a(base-1,n)+F(9) for base>=9.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.

FORMULA

Conjectures from Colin Barker, Jun 04 2017: (Start)

G.f.: (1 - x^2 - 18*x^3) / ((1 - x)*(1 - 10*x - 9*x^2)).

a(n) = 1 + (5-sqrt(34))^n + (5+sqrt(34))^n for n>0.

a(n) = 11*a(n-1) - a(n-2) - 9*a(n-3) for n>3.

(End)

PROG

(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>9)+($[(i+1)mod N]`-$[i]`>9))

CROSSREFS

Sequence in context: A289344 A240392 A044724 * A163447 A254600 A060499

Adjacent sequences:  A125465 A125466 A125467 * A125469 A125470 A125471

KEYWORD

nonn,base

AUTHOR

R. H. Hardin, Dec 28 2006

STATUS

approved

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Last modified October 25 05:19 EDT 2021. Contains 348239 sequences. (Running on oeis4.)