A207667 Numbers n such that phi(n) divides n+2.

1, 2, 4, 6, 10, 30, 70, 510, 2590, 131070, 3359230, 167247870, 8589934590, 13985925344264190

Offset

1,2

Comments

Contains 2 * A203966 as a subsequence. - Max Alekseyev, Oct 27 2023

Links

Table of n, a(n) for n=1..14.

Mathematica

Select[Range[50000000], Divisible[#+2, EulerPhi[#]]&]

Crossrefs

Cf. A000010, A050474, A207574, A202855, A203966.

Sequence in context: A095007 A005194 A171447 * A085809 A073308 A058960

Adjacent sequences: A207664 A207665 A207666 * A207668 A207669 A207670

Keyword

nonn,more,hard

Author

José María Grau Ribas, Feb 19 2012

Extensions

a(12)-a(13) from Donovan Johnson, Mar 01 2012

a(14) from Max Alekseyev, Oct 27 2023

Status

approved