login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A190804 Increasing sequence generated by these rules: a(1)=1, and if x is in a then 2x-1 and 3x are in a. 4

%I #10 Jul 13 2013 12:04:09

%S 1,3,5,9,15,17,27,29,33,45,51,53,57,65,81,87,89,99,101,105,113,129,

%T 135,153,159,161,171,173,177,195,197,201,209,225,243,257,261,267,269,

%U 297,303,305,315,317,321,339,341,345,353,387,389,393,401,405,417,449

%N Increasing sequence generated by these rules: a(1)=1, and if x is in a then 2x-1 and 3x are in a.

%C See A190803.

%H Reinhard Zumkeller, <a href="/A190804/b190804.txt">Table of n, a(n) for n = 1..10000</a>

%t h = 2; i = -1; j = 3; k = 0; f = 1; g = 10 ;

%t a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]] (* A190804 *)

%t b = (a + 1)/2; c = a/3; r = Range[1, 500];

%t d = Intersection[b, r] (* A190803 conjectured *)

%t e = Intersection[c, r] (* A190844 *)

%o import Data.Set (singleton, deleteFindMin, insert)

%o a190804 n = a190804_list !! (n-1)

%o a190804_list = 1 : f (singleton 3)

%o where f s = m : (f $ insert (2*m-1) $ insert (3*m) s')

%o where (m, s') = deleteFindMin s

%o -- _Reinhard Zumkeller_, Jun 01 2011

%Y Cf. A190803.

%K nonn

%O 1,2

%A _Clark Kimberling_, May 20 2011

%E a(56) = 449 inserted by _Reinhard Zumkeller_, Jun 01 2011

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 28 05:39 EDT 2024. Contains 371235 sequences. (Running on oeis4.)