A005242 A self-generating sequence. (Formerly M0971)

1, 2, 4, 5, 8, 10, 12, 14, 15, 16, 19, 20, 21, 24, 25, 27, 28, 32, 33, 34, 37, 38, 40, 42, 43, 44, 46, 47, 48, 51, 53, 54, 56, 57, 58, 59, 61, 62, 63, 64, 66, 68, 69, 72, 73, 74, 77, 79, 81, 83, 84, 86, 88, 89, 91, 92, 94, 96, 97, 98, 100

Offset

1,2

Comments

Presumably this is the lexicographically earliest sequence of distinct positive numbers with the property that sums of two or three consecutive earlier terms are excluded. - N. J. A. Sloane, Jan 07 2021

References

R. K. Guy, Unsolved Problems in Number Theory, E30.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

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

Eric Weisstein's World of Mathematics, Prime Number of Measurement.

Prog

(Haskell)
import Data.List ((\\))
a005242 n = a005242_list !! (n-1)
a005242_list = f [1..] 0 0 where
   f (x:xs) y z = x : f (xs \\ [x + y, x + y + z]) x y
-- Reinhard Zumkeller, May 23 2013

Crossrefs

Cf. A002048, A033627.

Sequence in context: A188972 A047612 A123886 * A323976 A188975 A115392

Adjacent sequences: A005239 A005240 A005241 * A005243 A005244 A005245

Keyword

nonn

Author

N. J. A. Sloane

Extensions

More terms from Jud McCranie, Feb 15 1997

Status

approved