A291205 Numbers n such that psi(n) = phi(m) has no solution for any m (psi(n) = A001615(n) and phi(m) = A000010(m)).

2, 13, 37, 50, 58, 61, 67, 73, 74, 89, 97, 111, 113, 122, 151, 157, 169, 173, 181, 183, 193, 229, 233, 241, 250, 257, 259, 274, 277, 283, 298, 307, 313, 314, 317, 337, 349, 353, 373, 386, 389, 394, 397, 401, 409, 421, 427, 433, 449, 453, 457, 466, 481, 487, 507, 509, 514, 541, 543, 547, 554, 557, 562

Offset

1,1

Comments

Numbers n such that psi(n) is not a totient number (A002202) where psi(n) = A001615(n).

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Example

58 is a term because psi(58) = 90 is not a term of A002202.

Prog

(PARI) a001615(n) = n*sumdivmult(n, d, issquarefree(d)/d);
isok(n) = !istotient(a001615(n)); \\ after Charles R Greathouse IV at A001615

Crossrefs

Cf. A000010, A001615, A002202.

Sequence in context: A085497 A320515 A265775 * A005113 A239196 A072857

Adjacent sequences: A291202 A291203 A291204 * A291206 A291207 A291208

Keyword

nonn,easy

Author

Altug Alkan, Aug 21 2017

Status

approved