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A126370 Number of base 16 n-digit numbers with adjacent digits differing by one or less. 4
1, 16, 46, 134, 392, 1150, 3380, 9948, 29310, 86430, 255044, 753040, 2224514, 6574100, 19435570, 57477542, 170028792, 503102142, 1488974870, 4407636908, 13049761478, 38642911632, 114446028208, 338991739166, 1004221622462 (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..24.

FORMULA

G.f.: (1+7*x-70*x^2+139*x^3-5*x^4-161*x^5+48*x^6+39*x^7-5*x^8) / (1-9*x+28*x^2-29*x^3-15*x^4+39*x^5-6*x^6-9*x^7+x^8) (conjectured). - Colin Barker, Jul 18 2017

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: A124709 A244094 A235549 * A133345 A253231 A253350

Adjacent sequences: A126367 A126368 A126369 * A126371 A126372 A126373

KEYWORD

nonn,base

AUTHOR

R. H. Hardin, Dec 26 2006

STATUS

approved

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Last modified March 25 07:51 EDT 2023. Contains 361511 sequences. (Running on oeis4.)