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A124852 Number of base 10 circular n-digit numbers with adjacent digits differing by 2 or less. 1
1, 10, 44, 160, 672, 2860, 12482, 55198, 246712, 1111372, 5037174, 22940158, 104870790, 480863770, 2210197754, 10178143810, 46942294232, 216761695840, 1001878336772, 4634206919128, 21448419453382, 99316222901062 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

[Empirical] a(base,n)=a(base-1,n)+A005191(n+1) for base>=2.int(n/2)+1

LINKS

Table of n, a(n) for n=0..21.

FORMULA

G.f.: (1 - x - 27*x^2 + 27*x^3 + 201*x^4 - 313*x^5 + 8*x^6 + 112*x^7 - 7*x^8 - 9*x^9) / ((1 - x)*(1 + x)*(1 - 4*x + x^2 + x^3)*(1 - 7*x + 11*x^2 - x^4)) (conjectured). - Colin Barker, Jun 01 2017

PROG

(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>2)+($[(i+1)mod N]`-$[i]`>2))

CROSSREFS

Sequence in context: A005720 A060326 A200448 * A220923 A220994 A097416

Adjacent sequences:  A124849 A124850 A124851 * A124853 A124854 A124855

KEYWORD

nonn,base

AUTHOR

R. H. Hardin, Dec 28 2006

STATUS

approved

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Last modified January 19 09:35 EST 2020. Contains 331048 sequences. (Running on oeis4.)