A276504 Numbers n such that phi(n) = phi(n+11), with Euler's totient function phi = A000010.

7, 11, 27, 33, 45, 63, 135, 165, 285, 304, 345, 765, 855, 964, 1144, 1575, 1744, 2134, 2295, 2805, 6424, 6604, 10725, 23584, 24244, 27645, 28875, 31174, 31354, 35445, 40755, 44164, 46672, 57046, 57057, 61444, 64005, 78975, 82095, 90195

Offset: 1

Author

Vincenzo Librandi, Sep 08 2016

Keywords

• nonn
• easy

Links

• Kevin Ford, Solutions of phi(n) = phi(n+k) and sigma(n) = sigma(n + k), arXiv:2002.12155 [math.NT], 2020.

Crossrefs

Cf. A000010.

Cf. similar sequences listed in A276503.

Programs

Magma

[n: n in [1..100000] | EulerPhi(n) eq EulerPhi(n+11)];

Mathematica

Select[Range[150000], EulerPhi[#] == EulerPhi[# + 11] &]