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A003410 Expansion of (1+x)(1+x^2)/(1-x-x^3).
(Formerly M0648)
+0
5
1, 2, 3, 5, 7, 10, 15, 22, 32, 47, 69, 101, 148, 217, 318, 466, 683, 1001, 1467, 2150, 3151, 4618, 6768, 9919, 14537, 21305, 31224, 45761, 67066, 98290, 144051, 211117, 309407, 453458, 664575, 973982, 1427440, 2092015, 3065997 (list; graph; listen)
OFFSET

0,2

REFERENCES

R. K. Guy, personal communication.

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

LINKS

S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.

S. Plouffe, 1031 Generating Functions and Conjectures, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.

FORMULA

a(n) = a(n-1) + a(n-3) for n>3, see also A000930. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Oct 26 2005

For n>1, a(n) = 2*A000930(n) + A000930(n-2). [From Gerald McGarvey (gerald.mcgarvey(AT)comcast.net), Sep 10 2008]

MAPLE

G:=series((1+x)*(1+x^2)/(1-x-x^3), x=0, 42): 1, seq(coeff(G, x^n), n=1..38);

A003410:=-(1+z)*(1+z**2)/(-1+z+z**3); [S. Plouffe in his 1992 dissertation.]

CROSSREFS

Essentially the same as A058278 and A097333, partial sums and first differences of A058278, first and second differences of itself and A038718. Equals A038718(n+1) + 1, n>0.

Sequence in context: A011972 A160571 A076972 this_sequence A018133 A116975 A134792

Adjacent sequences: A003407 A003408 A003409 this_sequence A003411 A003412 A003413

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

EXTENSIONS

More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Dec 11 2004

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Last modified December 2 11:54 EST 2009. Contains 167921 sequences.


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