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!)
A191211 Increasing sequence generated by these rules:  a(1)=1, and if x is in a then 1+2x and 1+x^2 are in a. 2
1, 2, 3, 5, 7, 10, 11, 15, 21, 23, 26, 31, 43, 47, 50, 53, 63, 87, 95, 101, 107, 122, 127, 175, 191, 203, 215, 226, 245, 255, 351, 383, 407, 431, 442, 453, 491, 511, 530, 677, 703, 767, 815, 863, 885, 907, 962, 983, 1023, 1061, 1355, 1407, 1535, 1631, 1727, 1771, 1815, 1850, 1925, 1967, 2047, 2123, 2210, 2501 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

See A191203.

LINKS

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

EXAMPLE

1 -> 2,3 -> 5,7,10 ->

MATHEMATICA

g = 11; Union[Flatten[NestList[{1 + 2 #, 1 + #^2} &, 1, g]]]

(* A191211; use g>10 to get all of first 60 terms *)

PROG

(Haskell)

import Data.Set (singleton, deleteFindMin, insert)

a191211 n = a191211_list !! (n-1)

a191211_list = f $ singleton 1 where

   f s = m : f (insert (2 * m + 1) $ insert (m ^ 2 + 1) s')

         where (m, s') = deleteFindMin s

-- Reinhard Zumkeller, Apr 18 2014

CROSSREFS

Cf. A191203.

Sequence in context: A266679 A285257 A317407 * A263133 A254860 A144726

Adjacent sequences:  A191208 A191209 A191210 * A191212 A191213 A191214

KEYWORD

nonn

AUTHOR

Clark Kimberling, May 29 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 June 18 07:25 EDT 2021. Contains 345098 sequences. (Running on oeis4.)