OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
201 is a term because both 201 and 1000 - 201 = 799 are semiprimes.
MAPLE
tc:= n -> 10^(1+ilog10(n))-n:
filter:= proc(n) numtheory:-bigomega(n)=2 and numtheory:-bigomega(tc(n))=2 end proc:
select(filter, [$1..1000]); # Robert Israel, Jul 02 2024
MATHEMATICA
Select[Range[500], PrimeOmega[#]==PrimeOmega[10^IntegerLength[#]-#]==2&] (* Harvey P. Dale, Jan 17 2013 *)
CROSSREFS
KEYWORD
easy,nonn,base
AUTHOR
Jason Earls, Jun 02 2004
STATUS
approved