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A126363 Number of base 9 n-digit numbers with adjacent digits differing by one or less. 4
1, 9, 25, 71, 203, 583, 1679, 4845, 14001, 40503, 117263, 339699, 984515, 2854281, 8277153, 24007543, 69642819, 202046535, 586220911, 1700972653, 4935747673, 14322646039, 41562779655, 120613013891, 350017652003, 1015758270153 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

[Empirical] a(base,n)=a(base-1,n)+3^(n-1) for base>=n; a(base,n)=a(base-1,n)+3^(n-1)-2 when base=n-1

LINKS

Table of n, a(n) for n=0..25.

FORMULA

Empirical G.f.: -(2*x^5+13*x^4-4*x^3-15*x^2+4*x+1) / ((x-1)*(x^4+6*x^3+x^2-4*x+1)). [Colin Barker, Nov 26 2012]

PROG

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

CROSSREFS

Sequence in context: A146589 A146866 A271731 * A036836 A125997 A199111

Adjacent sequences:  A126360 A126361 A126362 * A126364 A126365 A126366

KEYWORD

nonn,base

AUTHOR

R. H. Hardin, Dec 26 2006

STATUS

approved

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Last modified April 5 03:58 EDT 2020. Contains 333238 sequences. (Running on oeis4.)