A030637 Numbers with 19 divisors.

262144, 387420489, 3814697265625, 1628413597910449, 5559917313492231481, 112455406951957393129, 14063084452067724991009, 104127350297911241532841, 3244150909895248285300369, 210457284365172120330305161, 699053619999045038539170241

Offset: 1

Author

Jeff Burch

Keywords

• nonn
• easy

Comments

18th powers of primes. The n-th number with p divisors is equal to the n-th prime raised to power p-1, where p is prime. - Omar E. Pol, May 06 2008

Links

• R. J. Mathar, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000040, A030634, A030635, A030636.

Programs

Mathematica

Prime[Range[18]]^18 (* Vladimir Joseph Stephan Orlovsky, May 05 2011 *)

PARI

is(n)=isprimepower(n)==18 \\ Charles R Greathouse IV, Jun 19 2016

Formula

a(n)=A000040(n)^(19-1)=A000040(n)^(18). - Omar E. Pol, May 06 2008

Extensions

a(6) corrected, Mar 26 2007