A070287 - OEIS

A070287

Numbers n such that the equation lcm(sigma(x),phi(x))=n has solutions.

1, 3, 4, 12, 14, 24, 28, 36, 48, 60, 72, 78, 84, 96, 120, 144, 168, 180, 192, 240, 248, 264, 288, 312, 336, 360, 420, 432, 480, 496, 576, 620, 672, 684, 720, 780, 792, 798, 840, 864, 924, 936, 960, 1008, 1056, 1080, 1092, 1104, 1176, 1240, 1260, 1344, 1368

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..53.

PROG

(PARI) for(n=1, 2000, if(0<sum(i=1, n, if(lcm(sigma(i), eulerphi(i))-n, 0, 1)), print1(n, ", ")))

CROSSREFS

Sequence in context: A324653 A094025 A336612 * A124637 A352907 A047173

Adjacent sequences: A070284 A070285 A070286 * A070288 A070289 A070290

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, May 10 2002

STATUS

approved