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A126371 Number of base 17 n-digit numbers with adjacent digits differing by one or less. 4
1, 17, 49, 143, 419, 1231, 3623, 10677, 31497, 92991, 274727, 812089, 2401661, 7105541, 21029893, 62260511, 184377699, 546148863, 1618115031, 4795057355, 14212022443, 42129691565, 124906348517, 370372587127, 1098363570827 (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+8*x-77*x^2+140*x^3+62*x^4-266*x^5+17*x^6+132*x^7-6*x^8-10*x^9) / ((1-x)*(1-2*x-2*x^2)*(1-6*x+9*x^2+4*x^3-12*x^4+x^6)) (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: A049737 A146871 A146791 * A146799 A147201 A146775

Adjacent sequences:  A126368 A126369 A126370 * A126372 A126373 A126374

KEYWORD

nonn,base

AUTHOR

R. H. Hardin, Dec 26 2006

STATUS

approved

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Last modified February 25 08:42 EST 2020. Contains 332221 sequences. (Running on oeis4.)