OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
514 is in the sequence because 51 = 3*17.
MATHEMATICA
Select[Range[600], PrimeOmega[#]==2==PrimeOmega[FromDigits[ Most[ IntegerDigits[ #]]]]&] (* Harvey P. Dale, Oct 02 2014 *)
Select[Range[600], PrimeOmega[#]==PrimeOmega[Quotient[#, 10]]==2&] (* Harvey P. Dale, Mar 18 2023 *)
PROG
(PARI)
list(lim)=my(v=List(), t); forprime(p=2, sqrt(lim), t=p; forprime(q=p, lim\t, listput(v, t*q))); vecsort(Vec(v)) \\ From A001358
issemiprime(n) = n>0 && bigomega(n)==2
t=list(1000); for(n=1, #t, if(issemiprime(t[n]\10), print1(t[n], ", ")))
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Colin Barker, Jan 14 2014
STATUS
approved