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A126507 Number of base 12 n-digit numbers with adjacent digits differing by four or less. 1
1, 12, 88, 672, 5168, 39796, 306520, 2361008, 18186104, 140082072, 1079010248, 8311293248, 64019406944, 493122351856, 3798374049312, 29257739717488, 225363621979872, 1735908604096736, 13371185000068864, 102994240528644064 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

[Empirical] a(base,n)=a(base-1,n)+9^(n-1) for base>=4n-3; a(base,n)=a(base-1,n)+9^(n-1)-2 when base=4n-4.

LINKS

Table of n, a(n) for n=0..19.

FORMULA

G.f.: (1+4*x-8*x^2-14*x^3+6*x^4+6*x^5) / (1-8*x+18*x^3-2*x^4-6*x^5) (conjectured). - Colin Barker, Jul 17 2017

PROG

(S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>4)+($[i+1]`-$[i]`>4))

CROSSREFS

Cf. Base 12 differing by three or less A126480, two or less A126399, one or less A126366.

Sequence in context: A164608 A081009 A155635 * A181704 A009657 A012088

Adjacent sequences:  A126504 A126505 A126506 * A126508 A126509 A126510

KEYWORD

nonn,base

AUTHOR

R. H. Hardin, Dec 28 2006

STATUS

approved

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Last modified June 18 12:21 EDT 2021. Contains 345104 sequences. (Running on oeis4.)