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!)
A191143 Increasing sequence generated by these rules:  a(1)=1, and if x is in a then 3x+2 and 4x+1 are in a. 4
1, 5, 17, 21, 53, 65, 69, 85, 161, 197, 209, 213, 257, 261, 277, 341, 485, 593, 629, 641, 645, 773, 785, 789, 833, 837, 853, 1025, 1029, 1045, 1109, 1365, 1457, 1781, 1889, 1925, 1937, 1941, 2321, 2357, 2369, 2373, 2501, 2513, 2517, 2561, 2565, 2581, 3077, 3089, 3093, 3137, 3141, 3157, 3329, 3333, 3349, 3413, 4097, 4101 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

See A191113.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

MATHEMATICA

h = 3; i = 2; j = 4; k = 1; f = 1; g = 9;

a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]]  (* A191143 *)

b = (a - 2)/3; c = (a - 1)/4; r = Range[1, 1500];

d = Intersection[b, r] (* A191210 *)

e = Intersection[c, r] (* A191136 *)

m = (a + 1)/2 (* divisibility property *)

p = (a + 3)/4 (* divisibility property *)

PROG

(Haskell)

import Data.Set (singleton, deleteFindMin, insert)

a191143 n = a191143_list !! (n-1)

a191143_list = f $ singleton 1

   where f s = m : (f $ insert (3*m+2) $ insert (4*m+1) s')

             where (m, s') = deleteFindMin s

-- Reinhard Zumkeller, Jun 01 2011

CROSSREFS

Cf. A191113.

Sequence in context: A305478 A262620 A191210 * A032376 A145818 A029986

Adjacent sequences:  A191140 A191141 A191142 * A191144 A191145 A191146

KEYWORD

nonn

AUTHOR

Clark Kimberling, May 28 2011

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 July 26 22:49 EDT 2021. Contains 346300 sequences. (Running on oeis4.)