A050688 Numbers k such that A000422(k) is nonsquarefree.
8, 9, 15, 17, 18, 26, 27, 35, 36, 44, 45, 53, 54, 56, 62, 63, 71, 72, 80, 81, 89, 90, 98, 99, 107, 108, 109
Offset: 1
Examples
a(2)=9 because 987654321 = 3^2 * 17^2 * 379721.
Links
- Patrick De Geest, Reversed Smarandache Concatenated Numbers, Prime factors from n down to 1
- M. Fleuren, Factors and primes of Smarandache sequences.
- M. Fleuren, Smarandache Factors and Reverse factors
- Carlos Rivera, Puzzle 8. Primes by Listing, The Prime Puzzles & Problems Connection.
Extensions
Definition corrected by Charles R Greathouse IV, Sep 20 2012
a(17)-a(24) and name corrected by Sean A. Irvine, Aug 17 2021
a(25)-a(27) from Daniel Suteu, Aug 18 2021