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A152775 Numbers with 3n binary digits where every run length is 3, written in binary. 4
111, 111000, 111000111, 111000111000, 111000111000111, 111000111000111000, 111000111000111000111, 111000111000111000111000, 111000111000111000111000111, 111000111000111000111000111000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A152776 written in base 2.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..100

Index entries for linear recurrences with constant coefficients, signature (1000,1,-1000).

FORMULA

From Colin Barker, Apr 20 2014: (Start)

a(n) = (-1001-999*(-1)^n+2^(4+3*n)*125^(1+n))/18018.

a(n) = 1000*a(n-1)+a(n-2)-1000*a(n-3).

G.f.: 111*x / ((x-1)*(x+1)*(1000*x-1)). (End).

EXAMPLE

n ... a(n) .............. A152776(n)

1 ... 111 ............... 7

2 ... 111000 ............ 56

3 ... 111000111 ......... 455

4 ... 111000111000 ...... 3640

5 ... 111000111000111 ... 29127

MATHEMATICA

FromDigits/@Table[Flatten[PadRight[{}, n, {a, b}]/.{a->{1, 1, 1}, b->{0, 0, 0}}], {n, 10}] (* Harvey P. Dale, Mar 23 2012 *)

CoefficientList[Series[111/((x - 1) (x + 1) (1000 x - 1)), {x, 0, 20}], x] (* Vincenzo Librandi, Apr 21 2014 *)

PROG

(PARI) Vec(111*x / ((x-1)*(x+1)*(1000*x-1)) + O(x^100)) \\ Colin Barker, Apr 20 2014

CROSSREFS

Cf. A043291, A153435, A152776.

Sequence in context: A262641 A145698 A244845 * A242646 A242645 A262647

Adjacent sequences:  A152772 A152773 A152774 * A152776 A152777 A152778

KEYWORD

easy,nonn,base

AUTHOR

Omar E. Pol, Jan 18 2009

STATUS

approved

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Last modified July 18 01:14 EDT 2019. Contains 325110 sequences. (Running on oeis4.)