OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
15=T(5) and 51=3*17 is semiprime.
MATHEMATICA
Select[Accumulate[Range[200]], PrimeOmega[FromDigits[Reverse[ IntegerDigits[ #]]]] == 2&] (* Harvey P. Dale, Nov 14 2013 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Giovanni Resta, Jan 31 2006
STATUS
approved