OFFSET
1,6
COMMENTS
a(n) = tau(n) for numbers n: 1, 6, 14, 22, 30, 38, 42, 46, 54, 56, 60, 62, 66, 70, 78, 86, 94, 96, 102, ...
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..65537
FORMULA
a(p) = 1 for p = primes (A000040).
EXAMPLE
a(6) = gcd(tau(6), sigma(6), pod(6)) = gcd(4, 12, 36) = 4.
MATHEMATICA
a[n_] := GCD @@ {(d = DivisorSigma[0, n]), DivisorSigma[1, n], n^(d/2)}; Array[a, 100] (* Amiram Eldar, Aug 01 2020 *)
PROG
(Magma) [GCD([#Divisors(n), &+Divisors(n), &*Divisors(n)]): n in [1..100]]
(PARI)
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Aug 01 2020
EXTENSIONS
Data section extended up to a(105) by Antti Karttunen, Aug 10 2020
STATUS
approved