OFFSET
1,2
LINKS
FORMULA
EXAMPLE
For n = 6; divisors d of 6: {1, 2, 3, 6}; tau(d): {1, 2, 2, 4}; LCM_{d|6} tau(d) = 4; a(6) = 4/1 + 4/2 + 4/2 + 4/4 = 9.
MATHEMATICA
Table[LCM @@ DivisorSigma[0, Divisors@ n] Sum[1/DivisorSigma[0, d], {d, Divisors@ n}], {n, 74}] (* Michael De Vlieger, Dec 09 2015 *)
PROG
(Magma) [&+[LCM([NumberOfDivisors(d): d in Divisors(n)]) / NumberOfDivisors(d): d in Divisors(n) ]: n in [1..100]]
(PARI)
A253139(n) = my(d = divisors(n)); lcm(vector(#d, k, numdiv(d[k]))); \\ This function from Michel Marcus, Jan 23 2015
CROSSREFS
KEYWORD
nonn,mult
AUTHOR
Jaroslav Krizek, Dec 08 2015
EXTENSIONS
More terms from Antti Karttunen, Nov 24 2017
STATUS
approved