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.

A063639 Primes of the form p*q*r - 1, where p, q and r are primes (not necessarily distinct).

Original entry on oeis.org

7, 11, 17, 19, 29, 41, 43, 67, 97, 101, 109, 113, 137, 163, 173, 181, 211, 229, 241, 257, 281, 283, 317, 331, 337, 353, 373, 401, 409, 433, 523, 547, 577, 601, 617, 641, 653, 677, 691, 709, 761, 787, 821, 829, 853, 907, 937, 941, 977, 1009, 1021, 1033, 1051
Offset: 1

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Author

Reinhard Zumkeller, Jul 21 2001

Keywords

Crossrefs

Programs

  • Haskell
    a063639 n = a063639_list !! (n-1)
    a063639_list = [p | p <- a000040_list, a001222 (p+1) == 3]
    -- Reinhard Zumkeller, Feb 04 2012
  • Mathematica
    Take[Select[Union[Times@@#-1&/@Tuples[Prime[Range[60]],3]],PrimeQ],60] (* Harvey P. Dale, Jan 23 2012 *)
  • PARI
    { n=0; for (m=1, 10^9, p=prime(m); if (bigomega(p + 1) == 3, write("b063639.txt", n++, " ", p); if (n==1000, break)) ) } \\ Harry J. Smith, Aug 26 2009