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A124999 Number of base 5 circular n-digit numbers with adjacent digits differing by 3 or less. 2
1, 5, 23, 101, 467, 2165, 10055, 46709, 216995, 1008101, 4683383, 21757829, 101081459, 469599317, 2181641639, 10135364501, 47086382915, 218751625157, 1016265649367, 4721317472933, 21934066839827, 101900219778101, 473403079631879, 2199312977861813 (list; graph; refs; listen; history; text; internal format)
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..23.

FORMULA

Conjectures from Colin Barker, Jun 02 2017: (Start)

G.f.: (1 - 2*x)*(1 + 2*x + 3*x^2) / ((1 - x)*(1 - 4*x - 3*x^2)).

a(n) = 1 + (2-sqrt(7))^n + (2+sqrt(7))^n for n>0.

a(n) = 5*a(n-1) - a(n-2) - 3*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]`-$[(i+1)mod N]`>3)+($[(i+1)mod N]`-$[i]`>3))

CROSSREFS

Sequence in context: A274322 A085350 A113443 * A258431 A120902 A054441

Adjacent sequences:  A124996 A124997 A124998 * A125000 A125001 A125002

KEYWORD

nonn,base

AUTHOR

R. H. Hardin, Dec 28 2006

STATUS

approved

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Last modified August 5 07:54 EDT 2021. Contains 346464 sequences. (Running on oeis4.)