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A126404 Number of base 17 n-digit numbers with adjacent digits differing by two or less. 3
1, 17, 79, 375, 1793, 8611, 41473, 200149, 967355, 4680655, 22667487, 109848049, 532610303, 2583482303, 12535495657, 60839746967, 295338090269, 1433900817213, 6962605102325, 33811619587041, 164207415391765 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

[Empirical] a(base,n)=a(base-1,n)+5^(n-1) for base>=2n-1; a(base,n)=a(base-1,n)+5^(n-1)-2 when base=2n-2.

LINKS

Table of n, a(n) for n=1..21.

FORMULA

G.f.: (1+7*x-64*x^2+48*x^3+171*x^4-100*x^5-120*x^6+50*x^7+20*x^8-6*x^9) / (1-10*x+27*x^2+4*x^3-73*x^4+19*x^5+50*x^6-14*x^7-8*x^8+2*x^9) (conjectured). - Colin Barker, Jul 18 2017

PROG

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

CROSSREFS

Cf. Base 17 differing by one or less A126371.

Sequence in context: A202138 A124898 A036429 * A142021 A172045 A060934

Adjacent sequences:  A126401 A126402 A126403 * A126405 A126406 A126407

KEYWORD

nonn,base

AUTHOR

R. H. Hardin, Dec 28 2006

EXTENSIONS

Edited by Charles R Greathouse IV, Aug 02 2010

STATUS

approved

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Last modified September 27 20:35 EDT 2020. Contains 337388 sequences. (Running on oeis4.)