login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A018909 Define the sequence S(a_0,a_1) by a_{n+2} is the least integer such that a_{n+2}/a_{n+1}>a_{n+1}/a_n for n >= 0. This is S(3,6). 1
3, 6, 13, 29, 65, 146, 328, 737, 1657, 3726, 8379, 18843, 42375, 95295, 214305, 481942, 1083821, 2437364, 5481296, 12326680, 27721007, 62340730, 140195723, 315280889, 709023335, 1594495915, 3585801902, 8063975053, 18134770251, 40782602860, 91714461944 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

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

D. W. Boyd, Linear recurrence relations for some generalized Pisot sequences, Advances in Number Theory ( Kingston ON, 1991) 333-340, Oxford Sci. Publ., Oxford Univ. Press, New York, 1993.

MAPLE

a:= proc(n) option remember; `if`(n<2, [3, 6][n+1],

       1 +floor(a(n-1)^2/a(n-2)))

    end:

seq(a(n), n=0..40);  # Alois P. Heinz, May 05 2014

MATHEMATICA

a[n_] := a[n] = Switch[n, 0, 3, 1, 6, _, 1 + Floor[a[n-1]^2/a[n-2]]];

a /@ Range[0, 40] (* Jean-Fran├žois Alcover, Nov 16 2020, after Alois P. Heinz *)

CROSSREFS

Sequence in context: A071014 A214260 A078061 * A093128 A005313 A213674

Adjacent sequences:  A018906 A018907 A018908 * A018910 A018911 A018912

KEYWORD

nonn

AUTHOR

R. K. Guy

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 28 16:41 EDT 2021. Contains 348329 sequences. (Running on oeis4.)