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

1,1

Links

Table of n, a(n) for n=1..27.

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.

Example

a(2)=9 because 987654321 = 3^2 * 17^2 * 379721.

Crossrefs

Cf. A013929, A000422, A048288, A048342, A050687, A050675.

Sequence in context: A101765 A306490 A256351 * A134334 A351048 A292188

Adjacent sequences: A050685 A050686 A050687 * A050689 A050690 A050691

Keyword

nonn,base,hard

Author

Patrick De Geest, Aug 15 1999

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

Status

approved