A076396 Smallest prime factor of n-th perfect power.

1, 2, 2, 3, 2, 5, 3, 2, 2, 7, 2, 3, 2, 11, 5, 2, 2, 13, 2, 2, 3, 3, 2, 17, 2, 7, 19, 2, 3, 2, 2, 23, 2, 5, 2, 3, 2, 29, 2, 31, 2, 2, 3, 2, 5, 2, 11, 37, 2, 3, 2, 41, 2, 2, 43, 2, 3, 2, 2, 3, 13, 47, 2, 7, 2, 3, 2, 2, 53, 2, 5, 5, 2, 3, 2, 3, 59, 2, 61, 2, 3, 2, 5, 2, 67, 2, 3, 2, 17, 71, 2, 73, 2, 3

Offset

1,2

Comments

a(n) = A020639(A001597(n)).

Links

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

Eric Weisstein's World of Mathematics, Perfect Powers.

Eric Weisstein's World of Mathematics, Least Prime Factor.

Formula

a(n) = A020639(A025478(n)).

Prog

(Haskell)
a076396 = a020639 . a025478 -- Reinhard Zumkeller, Mar 28 2014

Crossrefs

Cf. A025478, A076397, A076403.

Sequence in context: A118136 A356552 A258567 * A370834 A076397 A254269

Adjacent sequences: A076393 A076394 A076395 * A076397 A076398 A076399

Keyword

nonn,changed

Author

Reinhard Zumkeller, Oct 09 2002

Status

approved