A319865 Product of distinct prime factors of highly composite numbers (definition 1, A002182).

1, 2, 2, 6, 6, 6, 6, 6, 30, 30, 30, 30, 30, 30, 210, 210, 210, 210, 210, 210, 210, 210, 210, 210, 2310, 210, 210, 2310, 2310, 2310, 2310, 2310, 2310, 2310, 2310, 2310, 2310, 30030, 30030, 30030, 30030, 30030, 30030, 30030, 30030, 30030, 30030, 30030, 30030, 30030, 30030, 30030, 510510, 30030

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Highly Composite Number

Wikipedia, Highly composite number

Formula

a(n) = A007947(A002182(n)). - Michel Marcus, Sep 30 2018

Example

n  | A002182(n)                       | a(n)
---+----------------------------------+--------------------------
24 | 25200 = 2^4 * 3^2 * 5^2 * 7      |  210 = 2 * 3 * 5 * 7
25 | 27720 = 2^3 * 3^2 * 5   * 7 * 11 | 2310 = 2 * 3 * 5 * 7 * 11
26 | 45360 = 2^4 * 3^4 * 5   * 7      |  210 = 2 * 3 * 5 * 7
27 | 50400 = 2^5 * 3^2 * 5^2 * 7      |  210 = 2 * 3 * 5 * 7

Crossrefs

Cf. A002182, A007947, A108602, A112779, A272605.

Sequence in context: A086447 A324032 A196872 * A350657 A140219 A259225

Adjacent sequences: A319862 A319863 A319864 * A319866 A319867 A319868

Keyword

nonn

Author

Seiichi Manyama, Sep 29 2018

Status

approved