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A001612 a(n) = a(n-1) + a(n-2) - 1.
(Formerly M0974 N0364)
6
3, 2, 4, 5, 8, 12, 19, 30, 48, 77, 124, 200, 323, 522, 844, 1365, 2208, 3572, 5779, 9350, 15128, 24477, 39604, 64080, 103683, 167762, 271444, 439205, 710648, 1149852, 1860499, 3010350, 4870848, 7881197, 12752044, 20633240, 33385283, 54018522 (list; graph; refs; listen; history; internal format)
OFFSET

0,1

COMMENTS

a(n+3)=A^(n)B^(2)(1), n>=0, with compositions of Wythoff's complementary A(n):=A000201(n) and B(n)=A001950(n) sequences. See the W. Lang link under A135817 for the Wythoff representation of numbers (with A as 1 and B as 0 and the argument 1 omitted). E.g. 5=`00`, 8=`100`, 12=`1100`,..., in Wythoff code.

REFERENCES

F. Hazama, Spectra of graphs attached to the space of melodies, Discrete Math., 311 (2011), 2368-2383. See Table 5.2.

D. Jarden, Recurring Sequences. Riveon Lematematika, Jerusalem, 1966.

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

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

LINKS

T. D. Noe, Table of n, a(n) for n = 0..500

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.

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

FORMULA

G.f.: (3-4*x)/((1-x)*(1-x-x^2)). a(n)=a(n-1)+a(n-2)-1.

a(n) = 1+A000032(n).

MAPLE

A001612:=-(-2+3*z**2)/(z-1)/(z**2+z-1); [Conjectured by S. Plouffe in his 1992 dissertation. Gives sequence except for the initial 3.]

MATHEMATICA

Join[{b=3}, a=0; Table[c=a+b-1; a=b; b=c, {n, 100}]] (*From Vladimir Joseph Stephan Orlovsky, Mar 15 2011*)

PROG

(PARI) a(n)=fibonacci(n+1)+fibonacci(n-1)+1

CROSSREFS

Sequence in context: A039882 A164287 A086962 * A097092 A059320 A129601

Adjacent sequences:  A001609 A001610 A001611 * A001613 A001614 A001615

KEYWORD

nonn,easy

AUTHOR

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

EXTENSIONS

Additional comments from Michael Somos, Jun 01 2000.

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Last modified February 17 18:28 EST 2012. Contains 206067 sequences.