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A187892 a(0)=0, a(1)=6, a(n)=a(n-1)+a(n-2)-1. 0
0, 6, 5, 10, 14, 23, 36, 58, 93, 150, 242, 391, 632, 1022, 1653, 2674, 4326, 6999, 11324, 18322, 29645, 47966, 77610, 125575, 203184, 328758, 531941, 860698, 1392638, 2253335, 3645972, 5899306, 9545277, 15444582, 24989858, 40434439, 65424296, 105858734 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..37.

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

FORMULA

G.f. -x^2*(-6+7*x) / ( (x-1)*(x^2+x-1) ). - R. J. Mathar, Mar 15 2011

a(n) = 1+A022130(n-3), n>2. - R. J. Mathar, Mar 15 2011

a(n)=1-1/2*((1/2+1/2*sqrt(5))^n+(1/2-1/2*sqrt(5))^n)+11/10*sqrt(5)*((1/2+1/2*sqrt(5))^n-(1/2-1 /2*sqrt(5))^n). - Paolo P. Lava, Jun 06 2011

MATHEMATICA

Join[{a=0, b=6}, Table[c=a+b-1; a=b; b=c, {n, 100}]]

CROSSREFS

Cf. A000071, A001611, A001612, A187890.

Sequence in context: A229983 A251859 A100884 * A046615 A103132 A046627

Adjacent sequences:  A187889 A187890 A187891 * A187893 A187894 A187895

KEYWORD

nonn,easy

AUTHOR

Vladimir Joseph Stephan Orlovsky, Mar 15 2011

STATUS

approved

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Last modified November 16 02:33 EST 2018. Contains 317252 sequences. (Running on oeis4.)