

A015053


Smallest positive integer for which n divides a(n)^6.


3



1, 2, 3, 2, 5, 6, 7, 2, 3, 10, 11, 6, 13, 14, 15, 2, 17, 6, 19, 10, 21, 22, 23, 6, 5, 26, 3, 14, 29, 30, 31, 2, 33, 34, 35, 6, 37, 38, 39, 10, 41, 42, 43, 22, 15, 46, 47, 6, 7, 10, 51, 26, 53, 6, 55, 14, 57, 58, 59, 30, 61, 62, 21, 2, 65, 66, 67, 34, 69, 70, 71, 6, 73, 74, 15, 38, 77, 78
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OFFSET

1,2


COMMENTS

Multiplicative with a(p^e) = p^ceiling(e/6).  Christian G. Bower, May 16 2005
Differs from A007947 as follows: A007947(128)=2, a(128)=4; A007947(256)=2, a(256)=4; A007947(384)=6, a(384)=12; A007947(512)=2, a(512)=4; A007947(640)=10, a(640)=20, etc.  R. J. Mathar, Oct 28 2008


LINKS

Table of n, a(n) for n=1..78.
H. Ibstedt, Surfing on the Ocean of Numbers, Erhus Univ. Press, Vail, 1997.


PROG

(PARI) a(n) = my(f=factor(n)); for (i=1, #f~, f[i, 2] = ceil(f[i, 2]/6)); factorback(f); \\ Michel Marcus, Feb 15 2015


CROSSREFS

Cf. A019554, A019555, A053166, A015052.
Sequence in context: A056554 A088835 A007947 * A062953 A015052 A053166
Adjacent sequences: A015050 A015051 A015052 * A015054 A015055 A015056


KEYWORD

nonn,mult


AUTHOR

R. Muller (Research37(AT)aol.com)


EXTENSIONS

Corrected by David W. Wilson, Jun 04 2002


STATUS

approved



