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A343734 Highly composite 5-rough numbers: numbers that are divisible by neither 2 nor 3 whose number of divisors reaches a record. 1
1, 5, 25, 35, 175, 385, 1225, 1925, 5005, 13475, 25025, 85085, 175175, 425425, 1616615, 2977975, 8083075, 32757725, 37182145, 56581525, 185910725, 622396775, 929553625, 1301375075, 4647768125, 5391411025, 14315125825, 26957055125, 37739877175, 134785275625 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..30.

EXAMPLE

                                           number of

                                           divisors

   n   a(n)  prime factorization of a(n)    of a(n)

  --  -----  ----------------------------  ---------

   1      1  -                                  1

   2      5  5                                  2

   3     25  5^2                                3

   4     35  5   * 7                            4

   5    175  5^2 * 7                            6

   6    385  5   * 7   * 11                     8

   7   1225  5^2 * 7^2                          9

   8   1925  5^2 * 7   * 11                    12

   9   5005  5   * 7   * 11   * 13             16

  10  13475  5^2 * 7^2 * 11                    18

  11  25025  5^2 * 7   * 11   * 13             24

  12  85085  5   * 7   * 11   * 13   * 17      32

CROSSREFS

Cf. A000005, A002182, A007310, A053624.

Sequence in context: A070391 A084967 A249827 * A279541 A070390 A018724

Adjacent sequences:  A343731 A343732 A343733 * A343735 A343736 A343737

KEYWORD

nonn

AUTHOR

Jon E. Schoenfield, Jun 14 2021

STATUS

approved

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Last modified August 4 03:57 EDT 2021. Contains 346442 sequences. (Running on oeis4.)