A069824 - OEIS

A069824

Numbers n such that there is at least one x<n such that phi(x)sigma(x)=phi(n)sigma(n).

6, 22, 33, 42, 44, 56, 57, 62, 66, 68, 76, 78, 82, 96, 102, 108, 110, 114, 124, 132, 135, 136, 138, 140, 145, 148, 154, 159, 165, 168, 174, 176, 182, 183, 186, 189, 198, 204, 205, 213, 216, 220, 222, 224, 228, 231, 234, 246, 254, 258, 264, 267, 270, 282, 285

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..55.

PROG

(PARI) for(n=1, 500, if(prod(i=1, n-1, sigma(n)*eulerphi(n)-sigma(i)*eulerphi(i))==0, print1(n, ", ")))

CROSSREFS

Sequence in context: A037204 A296981 A035285 * A015709 A020195 A035134

Adjacent sequences: A069821 A069822 A069823 * A069825 A069826 A069827

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, Apr 28 2002

STATUS

approved