OFFSET
1,1
COMMENTS
The 3-almost primes are the numbers that are the product of exactly three (not necessarily distinct) primes.
EXAMPLE
a(1) = 8 = 2*2*2;
a(2) = 282 = 2*3*47;
a(3) = 52825 = 5*5*2113;
a(4) = 4528254 = 2*3*754709.
MATHEMATICA
d[n_]:=IntegerDigits[n]; t = {x = 8}; Do[i = 1; While[!PrimeOmega[y = FromDigits[Flatten[{z = d[i], d[x], Reverse[z]}]]]==3, i++]; AppendTo[t, x = y], {n, 13}]; t
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Michel Lagneau, Dec 01 2014
STATUS
approved