OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
Vaclav Kotesovec, Plot of a(n)/n^(3/2) and a(n)/(n*log(n)) for n = 1..100000
FORMULA
Is a(n) asymptotic to c*n^(3/2) with 1<c<1.5? [This conjecture is false, see plots. - Vaclav Kotesovec, Feb 15 2019]
EXAMPLE
1/phi(286) + 1/phi(287) = 1/120 + 1/240 = 1/80 so 286 is in the sequence.
MATHEMATICA
Select[Range[700], IntegerQ[1/(1/EulerPhi[ # ]+1/EulerPhi[ #+1])]&]
PROG
(PARI) isok(k) = numerator(1/eulerphi(k) + 1/eulerphi(k+1)) == 1; \\ Michel Marcus, Feb 18 2021
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Aug 27 2002
EXTENSIONS
Edited by Dean Hickerson, Aug 31 2002
STATUS
approved