OFFSET
1,7
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
Maxim Rytin, Finding the Inverse of Euler Totient Function (1999).
FORMULA
EXAMPLE
A005277(10)=86, therefore a(10)=1.
MATHEMATICA
IntegerExponent[Select[Range[2, 500, 2], invphi[#] == {}&], 2] (* Jean-François Alcover, Jul 01 2017, using Maxim Rytin's invphi function *)
PROG
(PARI) lista(nn)=forstep(n=2, nn, 2, if (!istotient(n), print1(valuation(n, 2), ", ")); ); \\ Michel Marcus, Jul 01 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Jon Perry, Jan 31 2003
EXTENSIONS
More terms from Jean-François Alcover, Jul 01 2017
Offset corrected by Charles R Greathouse IV, Jul 02 2017
STATUS
approved