A152453 Where records occur in A152235.

1, 2, 4, 12, 48, 144, 576, 720, 2880, 25920, 129600, 414720, 907200, 14515200, 58060800, 130636800, 522547200, 3265920000, 13063680000, 22861440000, 91445760000, 251475840000, 1005903360000, 16094453760000, 64377815040000, 81478172160000, 1030045040640000

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..87

Example

First few terms of A152235 are 1, 2, 2, 3, 2, 2, 2, 2, 3, 2, 2, 6, so a(1) to a(4) are 1, 2, 4, 12.

Prog

(Magma) W:=[]; r:=0; for n in [1..1300000] do a:=&*PrimeDivisors(NumberOfDivisors(n)); if r lt a then r:=a; Append(~W, n); end if; end for; print W;

Crossrefs

Cf. A152235 (largest squarefree number dividing the number of divisors of n), A152452 (records in A152235), A007947 (largest squarefree number dividing n).

Subsequence of A025487.

Sequence in context: A332235 A131387 A207647 * A368814 A277281 A172452

Adjacent sequences: A152450 A152451 A152452 * A152454 A152455 A152456

Keyword

nonn

Author

Klaus Brockhaus, Dec 04 2008

Extensions

a(15)-a(20) from Donovan Johnson, Jul 30 2011

More terms from Amiram Eldar, Sep 01 2019

Status

approved