1,1

Numbers which are either the 5th power of a prime or the product of a prime and the square of a different prime, i.e. numbers which are in A050997 (5th powers of primes) or A014612 (product of three primes) but not in A030078 (cubes of primes) or A007304 (product of three distinct primes) - Henry Bottomley (se16(AT)btinternet.com), Apr 25 2000

Also numbers which are the square root of the product of their proper divisors - Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Apr 21 2001

Numbers of the form p^5 or p^2*q, where p and q are distinct primes. Such numbers are multiplicatively 3-perfect (i.e. the product of divisors of a(n) equals {a(n)}^3). - Lekraj Beedassy (blekraj(AT)yahoo.com), Jul 13 2005

Amarnath Murthy, A note on the Smarandache Divisor sequences, Smarandache Notions Journal, Vol. 11, 1-2-3, Spring 2000.

Amarnath Murthy, Generalization of partition function introducing Smarandache factor partitions, Smarandache Notions Journal, Vol. 11, 1-2-3, Spring 2000.

R. J. Mathar, Table of n, a(n) for n = 1..521

Amarnath Murthy and Charles Ashbacher, Generalized Partitions and Some New Ideas on Number Theory and Smarandache Sequences, Hexis, Phoenix; USA 2005. See Section 1.4, 1.12.

M. L. Perez et al., eds., Smarandache Notions Journal

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

Union of A050997 and A054753. - Lekraj Beedassy (blekraj(AT)yahoo.com), Jul 13 2005

A000005(a(n))=6. - Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Oct 10 2009

f[n_]:=Length[Divisors[n]]==6; lst={}; Do[If[f[n], AppendTo[lst, n]], {n, 6!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Dec 14 2009]

Cf. A061117.

Sequence in context: A124626 A087245 A153501 this_sequence A162947 A070011 A084679

Adjacent sequences: A030512 A030513 A030514 this_sequence A030516 A030517 A030518

nonn

Jeff Burch (jmburch(AT)osprey.smcm.edu)