

A116935


Semiprimes (A001358) which are the concatenation of the numbers 1 through n for some n.


2




OFFSET

1,1


COMMENTS

Next term has 185 digits, and it is thus too large to be included. It is equal to the concatenation of the first 97 integers.  Giovanni Resta, Jun 15 2016


LINKS



FORMULA



EXAMPLE

a(1) = 123 = 3 * 41.
a(2) = 1234 = 2 * 617.
a(3) = 1234567 = 127 * 9721.
a(4) = 2 * 6172839455055606570758085909601061116212631364146515661667.


CROSSREFS



KEYWORD

base,nonn,less


AUTHOR



STATUS

approved



