A389279 Primes p such that phi(p+1) = phi(p+2).

2, 103, 163, 193, 2203, 2833, 38803, 131143, 407923, 936493, 1025503, 1231423, 1276903, 1788253, 1925563, 2521693, 2792143, 2847583, 3289933, 5003743, 5295883, 5710087, 6315307, 6986887, 13496383, 17168083, 19210063, 20171383, 22348363, 26879683, 27798703, 30837823, 35056243

Offset

1,1

Links

Table of n, a(n) for n=1..33.

Example

163 is a term because phi(163+1) = phi(163+2) = 80.

Mathematica

Select[Prime[Range[2*10^6]], Equal @@ EulerPhi[# + {1, 2}] &] (* Amiram Eldar, Sep 28 2025 *)

Crossrefs

Cf. A000010, A000040, A001274, A067890, A119705, A389277, A389278.

Sequence in context: A283624 A055693 A357767 * A215964 A106299 A176933

Adjacent sequences: A389276 A389277 A389278 * A389280 A389281 A389282

Keyword

nonn

Author

S. I. Dimitrov, Sep 28 2025

Status

approved