A190810 Increasing sequence generated by these rules: a(1)=1, and if x is in a then 2x+1 and 3x-1 are in a.

1, 2, 3, 5, 7, 8, 11, 14, 15, 17, 20, 23, 29, 31, 32, 35, 41, 44, 47, 50, 59, 63, 65, 68, 71, 83, 86, 89, 92, 95, 101, 104, 119, 122, 127, 131, 137, 140, 143, 149, 167, 173, 176, 179, 185, 188, 191, 194, 203, 209, 212, 239, 245, 248, 255, 257, 263, 266, 275, 281

Offset

1,2

Comments

See A190803.

Links

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

Mathematica

h = 2; i = 1; j = 3; k = -1; f = 1; g = 9 ;
a = Union[Flatten[NestList[{h # + i, j # + k} &, f, g]]]  (* A190810 *)
b = (a - 1)/2; c = (a + 1)/3; r = Range[1, 900];
d = Intersection[b, r] (* A190855 *)
e = Intersection[c, r] (* A190856 *)

Prog

(Haskell)
import Data.Set (singleton, deleteFindMin, insert)
a190810 n = a190810_list !! (n-1)
a190810_list = f $ singleton 1
   where f s = m : (f $ insert (2*m+1) $ insert (3*m-1) s')
             where (m, s') = deleteFindMin s
-- Reinhard Zumkeller, Jun 01 2011
(PARI) is(n)=if(n<7, n!=4, (n%3==1 && is(n\3)) || (n%2 && is(n\2))) \\ Charles R Greathouse IV, Jul 14 2016

Crossrefs

Cf. A190803, A190855, A190856.

Sequence in context: A186285 A375886 A190855 * A278591 A191121 A026401

Adjacent sequences: A190807 A190808 A190809 * A190811 A190812 A190813

Keyword

nonn

Author

Clark Kimberling, May 20 2011

Extensions

a(55)=255 inserted by Reinhard Zumkeller, Jun 01 2011

Status

approved