OFFSET
1,1
COMMENTS
No other terms below 10^24. Some large terms: 1039619980803100740810795122685, 32576974833437288924302842789885. - Max Alekseyev, Jul 28 2024
All listed terms represent solutions to phi(m) = (m+3)/2 such that (m-1)/2 is an even squarefree number. Cf. A350777. - Max Alekseyev, Jul 21 2024
a(1)=2 is the only even term below 10^100000. - Max Alekseyev, Jul 22 2024
EXAMPLE
21 is a term since 21-1 = 2^2*5^1 and (2*5)+(2*1) = 12 = phi(21).
CROSSREFS
KEYWORD
nonn,more,hard
AUTHOR
EXTENSIONS
More terms from Jud McCranie
Corrected example and a(11)-a(14) from Donovan Johnson, Nov 14 2010
a(15)-a(17) from Max Alekseyev, Jul 21 2024
STATUS
approved