OFFSET
1,1
COMMENTS
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..1000
EXAMPLE
7 is a term since phi(7) = phi(9) = 6.
MATHEMATICA
Select[Range[1, 10^6, 2], EulerPhi[#] == EulerPhi[# + 2] &]
2#-1&/@SequencePosition[EulerPhi[Range[1, 151*10^4, 2]], {x_, x_}][[All, 1]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Apr 15 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Apr 03 2020
STATUS
approved