OFFSET
1,1
LINKS
Vassilis Papadimitriou, Table of n, a(n) for n = 1..10000.
FORMULA
EXAMPLE
For n = 1, a(1) = 4 is the multiplicative order of 2 mod 15 (15 is the first odd squarefree semiprime).
MATHEMATICA
MultiplicativeOrder[2, #] & /@ Select[Range[1, 350, 2], PrimeOmega[#] == 2 && PrimeNu[#] == 2 &] (* Amiram Eldar, Feb 24 2021 *)
PROG
(PARI) lista(nn) = {forstep(n=1, nn, 2, if ((bigomega(n) == 2) && (omega(n)==2), print1(znorder(Mod(2, n)), ", ")); ); } \\ Michel Marcus, Feb 05 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Vassilis Papadimitriou, Mar 13 2010
EXTENSIONS
Edited by Ray Chandler, Jan 09 2012
STATUS
approved