OFFSET
1,1
COMMENTS
A proper subset of A288452. All odd primes and all powers of 3 are pseudoperfect totient numbers. First term which has k factors counting multiplicity >1: 15, 153, 875, 4375, 62451, etc. First term which has k distinct factors >1: 15, 255, 21505, etc.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
MATHEMATICA
fQ[n_] := Module[{tots = Rest@ NestWhileList[ EulerPhi, n, # > 1 &]}, MemberQ[Total /@ Subsets[tots, Length[ tots]], n]]; Select[ Range[ 3, 440, 2], fQ@# && !PrimePowerQ@# &]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Amiram Eldar and Robert G. Wilson v, Jul 02 2017
STATUS
approved