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A234591 Number of binary words of length n which have no 0^b 1 1 0^a 1 0 1 0^b - matches, where a=1, b=2. 2
1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1023, 2044, 4084, 8160, 16304, 32576, 65088, 130048, 259841, 519173, 1037329, 2072626, 4141192, 8274272, 16532336, 33032288, 65999871, 131870458, 263482601, 526449078, 1051866919, 2101673384, 4199229896, 8390234112 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..1000

B. K. Miceli, J, Remmel, Minimal Overlapping Embeddings and Exact Matches in Words, PU. M. A., Vol. 23 (2012), No. 3, pp. 291-315.

Index entries for linear recurrences with constant coefficients, signature (2,0,0,0,0,0,0,-1,1,1).

FORMULA

G.f.: (1+x^8+x^9)/(1-2*x+x^8-x^9-x^10). - Alois P. Heinz, Jan 08 2014

MAPLE

a:= n-> coeff(series(-(x^9+x^8+1)/(x^10+x^9-x^8+2*x-1), x, n+1), x, n):

seq(a(n), n=0..40);  # Alois P. Heinz, Jan 08 2014

MATHEMATICA

a[n_ /; n<=9]:= 2^n; a[n_]:=a[n] =2*a[n-1] -a[n-8] +a[n-9] +a[n-10]; Table[a[n], {n, 0, 33}] (* Jean-Fran├žois Alcover, Mar 18 2014 *)

PROG

(PARI) my(x='x+O('x^40)); Vec((1+x^8+x^9)/(1-2*x+x^8-x^9-x^10)) \\ G. C. Greubel, Sep 14 2019

(MAGMA) R<x>:=PowerSeriesRing(Integers(), 40); Coefficients(R!( (1+x^8+x^9)/(1-2*x+x^8-x^9-x^10) )); // G. C. Greubel, Sep 14 2019

(Sage)

def A234591_list(prec):

    P.<x> = PowerSeriesRing(ZZ, prec)

    return P((1+x^8+x^9)/(1-2*x+x^8-x^9-x^10)).list()

A234591_list(40) # G. C. Greubel, Sep 14 2019

(GAP) a:=[1, 2, 4, 8, 16, 32, 64, 128, 256, 512];; for n in [11..40] do a[n]:=2*a[n-1]-a[n-8]+a[n-9]+a[n-10]; od; a; # G. C. Greubel, Sep 14 2019

CROSSREFS

Sequence in context: A008862 A145116 A172319 * A122265 A194633 A243088

Adjacent sequences:  A234588 A234589 A234590 * A234592 A234593 A234594

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Jan 01 2014

EXTENSIONS

a(17)-a(33) from Alois P. Heinz, Jan 08 2014

STATUS

approved

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Last modified October 14 17:27 EDT 2019. Contains 328022 sequences. (Running on oeis4.)