A207574 Numbers k such that phi(k)+2 divides k+2.

1, 6, 10, 14, 22, 26, 34, 38, 46, 58, 62, 74, 82, 86, 94, 106, 118, 122, 134, 142, 146, 158, 166, 178, 194, 202, 206, 214, 218, 226, 254, 262, 274, 278, 298, 302, 314, 326, 334, 346, 358, 362, 382, 386, 390, 394, 398, 422, 446, 454, 458, 466, 478

Offset

1,2

Comments

Consists of the even semiprimes (other than 4) together with A207575. - Charles R Greathouse IV, Jul 15 2013

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Mathematica

Select[Range[1000], Divisible[#+2, EulerPhi[#]+2]&]

Prog

(PARI) isA207574(n)={
        if( (n+2) % (eulerphi(n)+2) ==0, 1, 0) ;
}
{
for(n=1, 200,
        if (isA207574(n) , print(n)) ;
) ;
} /* R. J. Mathar, Feb 23 2012 */

Crossrefs

Cf. A000010, A207575, A202855, A203966.

Sequence in context: A055163 A342192 A119431 * A278972 A241817 A181628

Adjacent sequences: A207571 A207572 A207573 * A207575 A207576 A207577

Keyword

nonn,easy

Author

José María Grau Ribas, Feb 19 2012

Status

approved