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A006980 Compositions: 6th column of A048004.
(Formerly M1411)
2
1, 2, 5, 12, 28, 64, 143, 315, 687, 1485, 3186, 6792, 14401, 30391, 63872, 133751, 279177, 581040, 1206151, 2497895, 5161982, 10646564, 21919161, 45052841, 92461171, 189489255, 387830160, 792810956, 1618840800, 3301999647 (list; graph; refs; listen; history; text; internal format)
OFFSET

6,2

REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

J. L. Yucas, Counting special sets of binary Lyndon words, Ars Combin., 31 (1991), 21-29.

LINKS

Alois P. Heinz, Table of n, a(n) for n = 6..1000

Index to sequences with linear recurrences with constant coefficients, signature (2,1,0,-1,-2,-4,-5,-4,-3,-2,-1).

FORMULA

G.f.: x^6 / ((1-x-x^2-x^3-x^4-x^5) * (1-x-x^2-x^3-x^4-x^5-x^6)). - Alois P. Heinz, Oct 29 2008

MAPLE

a:= n-> (Matrix(11, (i, j)-> if i=j-1 then 1 elif j=1 then [2, 1, 0, -1, -2, -4, -5, -4, -3, -2, -1][i] else 0 fi)^n) [1, 7]: seq (a(n), n=6..40); # Alois P. Heinz, Oct 29 2008

PROG

(PARI) Vec(1/(1-x-x^2-x^3-x^4-x^5)/(1-x-x^2-x^3-x^4-x^5-x^6)+O(x^99)) \\ Charles R Greathouse IV, Jan 10 2013

CROSSREFS

Sequence in context: A192657 A006979 A019301 * A045623 A001410 A019486

Adjacent sequences:  A006977 A006978 A006979 * A006981 A006982 A006983

KEYWORD

nonn,easy

AUTHOR

Simon Plouffe

EXTENSIONS

Corrected definition: 6th column of A048004. - Geoffrey Critzer, Nov 09 2008

STATUS

approved

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Last modified December 18 10:38 EST 2014. Contains 252154 sequences.