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A318572 K-th squarefree number such that A318411(k) is not equal to the largest prime factor of k-th squarefree number. 2
35, 55, 70, 77, 95, 105, 110, 115, 119, 143, 154, 155, 161, 165, 187, 190, 203, 209, 210, 215, 221, 230, 231, 235, 238, 247, 253, 285, 286, 287, 295, 299, 310, 319, 322, 323, 329, 330, 335, 345, 355, 357, 371, 374, 377, 385, 391, 395, 403, 406, 407, 413, 415, 418, 429, 430 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Seiichi Manyama, Table of n, a(n) for n = 1..5000

EXAMPLE

A005117(k) is k-th squarefree number.

A073482(k) is the largest prime factor of A005117(k).

A073482(k) = A318411(k) for 2 <= k <= 22.

-------+------------+------------+------------

    k  | A005117(k) | A073482(k) | A318411(k)

-------+------------+------------+------------

    23 |         35 |          7 |         13

    34 |         55 |         11 |         21

    44 |         70 |          7 |         13

    48 |         77 |         11 |         31

    60 |         95 |         19 |         37

    65 |        105 |          7 |         13

    69 |        110 |         11 |         21

    73 |        115 |         23 |         45

    75 |        119 |         17 |         49

    89 |        143 |         13 |         61

    94 |        154 |         11 |         31

    95 |        155 |         31 |         61

    99 |        161 |         23 |         67

   101 |        165 |         11 |         21

   115 |        187 |         17 |         81

   116 |        190 |         19 |         37

PROG

(Ruby)

require 'prime'

def A(n)

  s = 1

  flag = false

  while !flag

    s += 1

    flag = true

    (1..n - 1).each{|i|

      if i != ((i ** s) % n)

        flag = false

        break

      end

    }

  end

  s

end

def A318572(n)

  ary = []

  i = 2

  while ary.size < n

    pq = i.prime_division

    if pq.all?{|j| j[1] == 1}

      ary << i if A(i) != pq[-1][0]

    end

    i += 1

  end

  ary

end

p A318572(50)

CROSSREFS

Cf. A005117, A073482, A318411.

Sequence in context: A043135 A039312 A043915 * A171082 A121707 A267999

Adjacent sequences:  A318569 A318570 A318571 * A318573 A318574 A318575

KEYWORD

nonn

AUTHOR

Seiichi Manyama, Aug 29 2018

STATUS

approved

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Last modified April 7 01:11 EDT 2020. Contains 333291 sequences. (Running on oeis4.)