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.

A071699 Greater members of twin prime pairs of form (4*k+3, 4*k+5), k >= 0.

Original entry on oeis.org

5, 13, 61, 73, 109, 181, 193, 229, 241, 313, 349, 421, 433, 601, 661, 829, 1021, 1033, 1093, 1153, 1321, 1429, 1453, 1489, 1609, 1621, 1669, 1789, 1873, 1933, 2029, 2089, 2113, 2269, 2341, 2593, 2689, 2713, 3001, 3121, 3169, 3253, 3301
Offset: 1

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Author

Reinhard Zumkeller, Jun 04 2002

Keywords

Comments

Corresponding lesser members: A071698(n).

Crossrefs

Cf. A010051, subsequence of A016813.
Intersection of A006512 and A002144.

Programs

  • Haskell
    a071699 n = a071699_list !! (n-1)
    a071699_list = [x | x <- [5, 9 ..], a010051' x == 1, a010051' (x-2) == 1]
    -- Reinhard Zumkeller, Aug 05 2014
    
  • Magma
    [4*(k+1)+1:k in [0..1000]|IsPrime(4*k+3) and IsPrime(4*k+5)]; // Marius A. Burtea, Nov 06 2019
  • Mathematica
    #+2&/@Select[4Range[0,850]+3,PrimeQ[#]&&PrimeQ[#+2]&] (* Harvey P. Dale, Aug 24 2011 *)

Formula

a(n) = 2*A241557(n+1) + 1. - Hilko Koning, Nov 06 2019