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A269914 Number of ternary strings of length n with maximal run length two containing 112. 5
1, 5, 20, 71, 237, 761, 2377, 7278, 21945, 65375, 192861, 564387, 1640496, 4741103, 13634501, 39042437, 111379025, 316687006, 897796581, 2538530615, 7160768785, 20156241155, 56626360256, 158804376883, 444638710925, 1243115597929, 3470779612521, 9678320566654 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,2

LINKS

Table of n, a(n) for n=3..30.

Math StackExchange, Words built with 0,1,2

Marko Riedel, Maple code by total enumeration and by generating function.

FORMULA

G.f.: x^3*(x+1)*(x^2+x+1)/((2*x^2+2*x-1)*(x^4+3*x^3+3*x^2+x-1)).

MATHEMATICA

Drop[CoefficientList[Series[x^3 (x + 1) (x^2 + x + 1)/((2 x^2 + 2 x - 1) (x^4 + 3 x^3 + 3 x^2 + x - 1)), {x, 0, 30}], x], 3] (* Michael De Vlieger, Mar 08 2016 *)

CROSSREFS

Cf. A081038, A269915, A269916, A269917.

Sequence in context: A054444 A121332 A122695 * A066822 A137212 A270080

Adjacent sequences:  A269911 A269912 A269913 * A269915 A269916 A269917

KEYWORD

nonn

AUTHOR

Marko Riedel, Mar 07 2016

STATUS

approved

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Last modified January 17 06:34 EST 2019. Contains 319207 sequences. (Running on oeis4.)