OFFSET
0,6
LINKS
Max Alekseyev, Table of n, a(n) for n = 0..100
EXAMPLE
a(5)=180217597=7*25745371 and sigma(180217597)=(2^3)*(2^2*23^5)=2^5*23^5 and 180217597 is the smallest such number.
CROSSREFS
KEYWORD
nonn
AUTHOR
Walter Kehowski, Sep 06 2010
EXTENSIONS
Terms a(15) onward from Max Alekseyev, Mar 03 2014
STATUS
approved