cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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.

Original entry on oeis.org

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
Offset: 1

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Author

Clark Kimberling, May 29 2011

Keywords

Comments

See A191203.

Examples

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

Crossrefs

Cf. A191203.

Programs

  • 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
  • Mathematica
    g = 11; Union[Flatten[NestList[{1 + 2 #, 1 + #^2} &, 1, g]]]
    (* A191211; use g>10 to get all of first 60 terms *)