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.

A022004 Initial members of prime triples (p, p+2, p+6).

Original entry on oeis.org

5, 11, 17, 41, 101, 107, 191, 227, 311, 347, 461, 641, 821, 857, 881, 1091, 1277, 1301, 1427, 1481, 1487, 1607, 1871, 1997, 2081, 2237, 2267, 2657, 2687, 3251, 3461, 3527, 3671, 3917, 4001, 4127, 4517, 4637, 4787, 4931, 4967, 5231, 5477
Offset: 1

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Comments

Subsequence of A001359. - R. J. Mathar, Feb 10 2013
All terms are congruent to 5 (mod 6). - Matt C. Anderson, May 22 2015
Intersection of A001359 and A023201. - Zak Seidov, Mar 12 2016

Crossrefs

Cf. A073648, A098412, A372247 (subsequence).
Subsequence of A007529.

Programs

  • Magma
    [ p: p in PrimesUpTo(10000) | IsPrime(p+2) and IsPrime(p+6) ] // Vincenzo Librandi, Nov 19 2010
    
  • Maple
    A022004 := proc(n)
        if n= 1 then
            5;
        else
            for a from procname(n-1)+2 by 2 do
                if isprime(a) and isprime(a+2) and isprime(a+6) then
                    return a;
                end if;
            end do:
        end if;
    end proc: # R. J. Mathar, Jul 11 2012
  • Mathematica
    Select[Prime[Range[1000]], PrimeQ[#+2] && PrimeQ[#+6]&] (* Vladimir Joseph Stephan Orlovsky, Mar 30 2011 *)
    Transpose[Select[Partition[Prime[Range[1000]],3,1],Differences[#]=={2,4}&]][[1]] (* Harvey P. Dale, Dec 24 2011 *)
  • PARI
    is(n)=isprime(n)&&isprime(n+2)&&isprime(n+6) \\ Charles R Greathouse IV, Jul 01 2013
    
  • Python
    from sympy import primerange
    def aupto(limit):
      p, q, alst = 2, 3, []
      for r in primerange(5, limit+7):
        if p+2 == q and p+6 == r: alst.append(p)
        p, q = q, r
      return alst
    print(aupto(5477)) # Michael S. Branicky, May 11 2021