OFFSET
1,336
COMMENTS
a(n) tells how many times in total n occurs in A064987.
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..65537
FORMULA
a(n) = Sum_{d|n} [A000203(d)*d == n], where [ ] is the Iverson bracket.
EXAMPLE
336 has 20 divisors: [1, 2, 3, 4, 6, 7, 8, 12, 14, 16, 21, 24, 28, 42, 48, 56, 84, 112, 168, 336]. Only two of them, d=12 and d=14, satisfy sigma(d) = (336/d), thus a(336) = 2.
PROG
(PARI) A327153(n) = sumdiv(n, d, (n==d*sigma(d)));
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Sep 18 2019
STATUS
approved