OFFSET
1,2
COMMENTS
LINKS
C. K. Caldwell, The Prime Glossary, Number of divisors
W. Sierpinski, Number Of Divisors And Their Sum
EXAMPLE
2 is a member, since sigma(2) = 3, tau(3) = 2 and rad(2) = 2.
65856 is a member, since sigma(65856) = 203200, tau(203200) = 42 and rad(65856) = 42.
MAPLE
with(numtheory):for n from 1 to 10000000 do : t1:= ifactors(n)[2] : t2 :=mul(t1[i][1], i=1..nops(t1)):if tau(sigma(n)) = t2 then print (n): else fi: od :
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Lagneau, Feb 22 2010
EXTENSIONS
a(31)-a(38) from Donovan Johnson, Jan 14 2012
STATUS
approved