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A091294 Numbers n such that phi(n) = phi(3n+1). 1
75973, 301513, 2053393, 3404053, 4022573, 5399123, 6461473, 8395613, 9848813, 11804173, 14124133, 15680573, 17173333, 20705533, 23609083, 28988353, 30290563, 32845633, 35025943, 36791813, 39630803, 42598663, 43605943, 44116333, 53795083, 54396533, 54563693 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Is it accidental that most terms have form 10k+3?
LINKS
MATHEMATICA
Do[If[Equal[EulerPhi[n], EulerPhi[3*n+1]], Print[n]], {n, 1, 100000000}]
PROG
(PARI) is(n)=my(t=eulerphi(3*n+1)); t<n && t==eulerphi(n) \\ Charles R Greathouse IV, May 19 2013
CROSSREFS
Sequence in context: A243959 A236807 A251470 * A096518 A234895 A096888
KEYWORD
nonn
AUTHOR
Labos Elemer, Feb 19 2004
EXTENSIONS
a(20)-a(27) from Donovan Johnson, Jul 27 2011
STATUS
approved

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Last modified June 15 15:25 EDT 2024. Contains 373407 sequences. (Running on oeis4.)