OFFSET
1,2
COMMENTS
From David A. Corneth, Aug 24 2020: (Start)
a(35) <= 1289027059712000000.
a(36) <= 136064563937280.
a(37) = 207816012706349056.
a(38) <= 1835772101525504.
a(39) <= 418089296461824.
a(40) <= 11698803719536640.
gcd(m, tau(m), sigma(m), pod(m)) = gcd(m, tau(m), sigma(m)) which may ease the search.
(End)
EXAMPLE
For n = 6; a(6) = 90 because 90 is the smallest number with gcd(90, tau(90), sigma(90), pod(90)) = gcd(90, 12, 234, 531441000000) = 6.
PROG
(Magma) [Min([m: m in[1..10^5] | GCD([m, #Divisors(m), &+Divisors(m), &*Divisors(m)]) eq k]): k in [1..10]]
(PARI) a(n) = {for(i = 1, oo, f = factor(i); if(gcd([i, numdiv(f), sigma(f)]) == n, return(i)))} \\ David A. Corneth, Aug 24 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Aug 23 2020
EXTENSIONS
a(11) from Amiram Eldar, Aug 24 2020
More terms from Jaroslav Krizek and David A. Corneth, Aug 24 2020
STATUS
approved