A087268 Solutions to gcd(x, pi(x)) = 1, where pi is A000720.

1, 2, 3, 5, 7, 9, 11, 12, 13, 17, 18, 19, 21, 23, 25, 26, 28, 29, 31, 32, 34, 35, 36, 37, 41, 42, 43, 45, 47, 49, 52, 53, 55, 57, 59, 60, 61, 65, 67, 68, 69, 70, 71, 73, 74, 76, 79, 81, 83, 84, 85, 86, 87, 88, 89, 91, 95, 97, 98, 99, 101, 103, 104, 106, 107, 109, 110, 111

Offset

1,2

Links

Ivan Neretin, Table of n, a(n) for n = 1..10000

Example

All primes are included.

Mathematica

Flatten[Position[Table[GCD[w, PrimePi[w]], {w, 1, 256}], 1]

Prog

(PARI) isok(n) = gcd(n, primepi(n)) == 1; \\ Michel Marcus, Apr 22 2018

Crossrefs

Cf. A007053, A000720, A087266, A087267, A057809.

Sequence in context: A069149 A042996 A073040 * A106765 A190785 A186290

Adjacent sequences: A087265 A087266 A087267 * A087269 A087270 A087271

Keyword

nonn

Author

Labos Elemer, Sep 16 2003

Status

approved