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A126394 Number of base 7 n-digit numbers with adjacent digits differing by two or less. 3
1, 7, 29, 125, 543, 2363, 10287, 44787, 194995, 848979, 3696331, 16093291, 70067867, 305065387, 1328210699, 5782837835, 25177641963, 109619822123, 477268896747, 2077959947307, 9047137938475, 39389933855019 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

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=0..21.

Sergey Kitaev, Jeffrey Remmel, (a,b)-rectangle patterns in permutations and words, arXiv:1304.4286 [math.CO], 2013.

Index entries for linear recurrences with constant coefficients, signature (5,-2,-4,2).

FORMULA

G.f.: 1 -x*(7-6*x-6*x^2+4*x^3) / ( (x-1)*(2*x^3-2*x^2-4*x+1) ). - R. J. Mathar, Jun 06 2013

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 7 differing by one or less A126361.

Sequence in context: A327587 A055427 A048876 * A252832 A074468 A303091

Adjacent sequences:  A126391 A126392 A126393 * A126395 A126396 A126397

KEYWORD

nonn,base

AUTHOR

R. H. Hardin, Dec 28 2006

STATUS

approved

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Last modified November 21 04:39 EST 2019. Contains 329350 sequences. (Running on oeis4.)