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A317781 Number of binary words of length n containing exactly two (possibly overlapping) occurrences of the subword 01101. 2
1, 4, 13, 35, 92, 230, 562, 1333, 3106, 7114, 16090, 35968, 79637, 174812, 380903, 824469, 1774122, 3797436, 8089574, 17158409, 36250415, 76309260, 160102335, 334877607, 698461293, 1452964434, 3015112497, 6242510786, 12896941964, 26591579894, 54724833014 (list; graph; refs; listen; history; text; internal format)
OFFSET

8,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 8..2000

Index entries for linear recurrences with constant coefficients, signature (6,-12,5,18,-39,33,6,-42,47,-21,-9,20,-15,6,-1).

FORMULA

G.f.: x^8*(x-1)^2/(x^5-2*x^4+x^3-2*x+1)^3.

CROSSREFS

Column k=2 of A277751.

Sequence in context: A177155 A189595 A189602 * A271358 A306349 A268996

Adjacent sequences:  A317778 A317779 A317780 * A317782 A317783 A317784

KEYWORD

nonn,easy

AUTHOR

Alois P. Heinz, Aug 06 2018

STATUS

approved

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Last modified June 26 04:11 EDT 2019. Contains 324369 sequences. (Running on oeis4.)