OFFSET
1,2
COMMENTS
a(n) = 1 for infinitely many n.
a(n) = 1 iff A057021(n) = 1.
Not all terms are 1's or primes. For example, a(128) = 21. - Antti Karttunen, Dec 24 2018
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..16384
EXAMPLE
For n = 12; b(12) = 14/3, a(n) = 2 because b(2) = 3/2; 14/3 * 3/2 = 7 (integer).
PROG
(PARI) A176801(n) = { my(am=(sigma(n)/numdiv(n))); for(i=1, oo, if(1==denominator(am*(sigma(i)/numdiv(i))), return(i))); }; \\ Antti Karttunen, Dec 24 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Apr 26 2010
EXTENSIONS
More terms from Antti Karttunen, Dec 24 2018
STATUS
approved