OFFSET
1,36
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
FORMULA
a(A355033(n)) = n.
EXAMPLE
a(2) = 1 since the numbers with 2 divisors are all primes and thus have only 1 prime signature.
a(36) = 2 since numbers with 36 divisors have 2 prime signatures, p1^5 * p2^5 and p1 * p2 * p3^8, that correspond to numbers with 10 prime divisors (counted with multiplicity).
a(72) = 3 since numbers with 72 divisors have 3 prime signatures, p1 * p2^5 * p3^5, p1^2 * p2^2 * p3^7 and p1 * p2 * p3 * p4^8, that correspond to numbers with 11 prime divisors (counted with multiplicity).
MATHEMATICA
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Jun 16 2022
STATUS
approved