OFFSET
1,1
COMMENTS
EXAMPLE
a(2) = 415 = 5 * 83 = concatenation of 4 and 15, where 4 is the semiprime 2^2 and 15 is the semiprime 3 * 5.
a(3) = 410111 = 13 * 31547 = the concatenation of 4, 10, and 111 where 4 = 2^2, 10 = 2 * 5, and 111 = 3 * 37.
a(5) = 410106100310003 = 76871 * 5334991093 = Concatenate(4,10,106,1003,10003).
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Jonathan Vos Post, Aug 19 2012
STATUS
approved