The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A337645 a(1)=2; thereafter, a(n) = smallest number with at least two different prime factors that is missing from A336957 after A336957(n) has been found. 4
 2, 6, 10, 10, 10, 10, 10, 10, 10, 18, 20, 20, 20, 20, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 36, 36, 36, 36, 44, 44, 44, 44, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 54 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The initial 2 is an exception. For n>2, A336957(n) is required to have at least two different prime factors. It is conjectured that every number with at least two different prime factors will eventually appear in A336957. LINKS N. J. A. Sloane, Table of n, a(n) for n = 1..20000 EXAMPLE A336957 begins 1, 2, 6, 15, 35, 14, with A336957(6)=14. At that point 10 is the smallest legal candidate that has not yet appeared, so a(6) = 10. CROSSREFS Cf. A336957, A338052, A338058. Sequence in context: A122882 A136700 A054645 * A225271 A050425 A030405 Adjacent sequences:  A337642 A337643 A337644 * A337646 A337647 A337648 KEYWORD nonn AUTHOR Scott R. Shannon and N. J. A. Sloane, Sep 25 2020; corrected Oct 11 2020 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 28 16:56 EDT 2022. Contains 354907 sequences. (Running on oeis4.)