A082474 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

A082474

Numbers n such that n=phi(x)*sigma(x) for some x<=n.

1, 3, 8, 14, 24, 48, 60, 72, 78, 112, 120, 144, 168, 192, 234, 248, 288, 336, 360, 384, 480, 504, 528, 576, 620, 672, 720, 840, 864, 960, 1008, 1080, 1092, 1152, 1344, 1368, 1440, 1584, 1680, 1848, 1860, 1872, 1984, 2160, 2208, 2304, 2352, 2394, 2520, 2688

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Donovan Johnson, Table of n, a(n) for n = 1..1000

PROG

(PARI) isok(n) = {for (x=1, n, if (eulerphi(x)*sigma(x) == n, return (1)); ); return (0); } \\ Michel Marcus, Dec 04 2013

CROSSREFS

Sequence in context: A257644 A135940 A126430 * A245181 A241563 A055335

Adjacent sequences: A082471 A082472 A082473 * A082475 A082476 A082477

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Apr 27 2003

STATUS

approved