A066154 Numbers k such that phi(k) = sigma(k) - sigma(k-1).

574, 3496, 148708, 380276, 604504, 703402, 1223194, 1961218, 2375854, 5153085, 13182476, 15089116, 15624820, 18503524, 19402515, 22352968, 27366118, 41377798, 42917332, 51062116, 58911736, 60113914, 74657636, 75018856

Offset

1,1

Links

Harry J. Smith, Table of n, a(n) for n = 1..29

Example

phi(574) = 240 = 1008 - 768 = sigma(574) - sigma(573).

Mathematica

Select [Range[1, 10^7], EulerPhi[ # ] == DivisorSigma[1, # ] - DivisorSigma[1, # - 1] & ]

Prog

(PARI) isok(k) = { k > 1 && eulerphi(k) == sigma(k) - sigma(k - 1) } \\ Harry J. Smith, Feb 03 2010

Crossrefs

Sequence in context: A090495 A092291 A158371 * A321052 A369625 A291133

Adjacent sequences: A066151 A066152 A066153 * A066155 A066156 A066157

Keyword

nonn

Author

Joseph L. Pe, Dec 13 2001

Extensions

a(11)-a(24) from Harry J. Smith, Feb 03 2010

Status

approved