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A082474 Numbers n such that n=phi(x)*sigma(x) for some x<=n. 1
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

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Last modified September 29 05:48 EDT 2020. Contains 337425 sequences. (Running on oeis4.)