A070163 Primes arising in A070162.

3, 3, 2, 5, 7, 7, 7, 11, 11, 11, 13, 17, 23, 19, 23, 29, 23, 23, 31, 29, 31, 29, 43, 31, 31, 47, 37, 53, 47, 41, 59, 43, 47, 47, 47, 59, 53, 71, 59, 59, 61, 89, 67, 71, 71, 73, 109, 79, 107, 79, 107, 83, 83, 89, 131, 109, 127, 97, 137, 101, 139, 103, 107, 107, 109, 139

Offset: 1

Author

Labos Elemer, Apr 26 2002

Keywords

• nonn

Links

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

Crossrefs

Cf. A000010, A051953, A070162.

Programs

Mathematica

Do[s=n-EulerPhi[n]-1; If[PrimeQ[s], Print[s]], n, 1, 10000]

PARI

lista(kmax) = {my(p); for(k = 1, kmax, p = k - eulerphi(k) - 1; if(isprime(p), print1(p, ", ")));} \\ Amiram Eldar, Nov 07 2024

Formula

a(n) = A070162(n) - A000010(A070162(n)) - 1 = A051953(A070162(n)) - 1.