[go: up one dir, main page]

login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A324529
a(n) = lcm(sigma(n), pod(n)) where sigma(k) = the sum of divisors of k (A000203) and pod(n) = the product of divisors of k (A007955).
5
1, 6, 12, 56, 30, 36, 56, 960, 351, 900, 132, 12096, 182, 1176, 1800, 31744, 306, 75816, 380, 168000, 14112, 4356, 552, 1658880, 3875, 14196, 29160, 21952, 870, 810000, 992, 2064384, 17424, 31212, 58800, 917070336, 1406, 21660, 85176, 23040000, 1722, 6223392
OFFSET
1,2
FORMULA
a(n) = pod(n) for numbers n in A145551.
a(n) = sigma(n) * pod(n) for numbers n in A014567.
EXAMPLE
For n=4: a(4) = lcm(sigma(4), pod(4)) = lcm(7, 8) = 56.
PROG
(Magma) [LCM(SumOfDivisors(n), &*[d: d in Divisors(n)]): n in [1.. 1000]]
(PARI) a(n) = my(d=divisors(n)); lcm(vecsum(d), vecprod(d)); \\ Michel Marcus, Mar 05 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Mar 05 2019
STATUS
approved