cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A228057 Odd numbers of the form p * m^2, where p is prime and m > 1.

Original entry on oeis.org

27, 45, 63, 75, 99, 117, 125, 147, 153, 171, 175, 207, 243, 245, 261, 275, 279, 325, 333, 343, 363, 369, 387, 405, 423, 425, 475, 477, 507, 531, 539, 549, 567, 575, 603, 605, 637, 639, 657, 675, 711, 725, 747, 775, 801, 833, 845, 847, 867, 873, 891, 909, 925
Offset: 1

Views

Author

T. D. Noe, Aug 13 2013

Keywords

Comments

This sequence is the second step toward candidates for odd perfect numbers, A228058.

Crossrefs

Programs

  • Haskell
    a228057 n = a228057_list !! (n-1)
    a228057_list = filter odd a228056_list -- Reinhard Zumkeller, Aug 14 2013
  • Mathematica
    nn = 1000; Union[Select[Flatten[Table[p*n^2, {p, Prime[Range[2, PrimePi[nn/4]]]}, {n, 3, Sqrt[nn/2], 2}]], # < nn &]]