OFFSET
1,2
EXAMPLE
a(1)=1 because the first semiprime is 4 = 100_2.
a(2)=2 because the second semiprime is 6 = 110_2.
PROG
(PARI) lista(nn) = {for (n=2, nn, if (bigomega(n)==2, print1(norml2(binary(n)), ", ")); ); } \\ Michel Marcus, Jun 05 2013
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Juri-Stepan Gerasimov, May 18 2010
EXTENSIONS
a(56) corrected by R. J. Mathar, May 23 2010
STATUS
approved