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.

A060229 Smaller member of a twin prime pair whose mean is a multiple of A002110(3)=30.

Original entry on oeis.org

29, 59, 149, 179, 239, 269, 419, 569, 599, 659, 809, 1019, 1049, 1229, 1289, 1319, 1619, 1949, 2129, 2309, 2339, 2549, 2729, 2789, 2969, 2999, 3119, 3299, 3329, 3359, 3389, 3539, 3929, 4019, 4049, 4229, 4259, 4649, 4799, 5009, 5099, 5279, 5519, 5639
Offset: 1

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Author

Labos Elemer, Mar 21 2001

Keywords

Comments

Equivalently, smaller of twin prime pair with primes in different decades.
Primes p such that p and p+2 are prime factors of Fibonacci(p-1) and Fibonacci(p+1) respectively. - Michel Lagneau, Jul 13 2016
The union of this sequence and A282326 gives A132243. - Martin Renner, Feb 11 2017
The union of {3,5}, A282321, A282323 and this sequence gives A001359. - Martin Renner, Feb 11 2017
The union of {3,5,7}, A282321, A282322, A282323, A282324, this sequence and A282326 gives A001097. - Martin Renner, Feb 11 2017
Number of terms less than 10^k, k=2,3,4,...: 2, 11, 72, 407, 2697, 19507, 146516, ... - Muniru A Asiru, Jan 29 2018

Examples

			For the pair {149,151} (149 + 151)/2 = 5*30.
		

Crossrefs

Programs

  • GAP
    Filtered(List([0..200], k -> 30*k-1), n -> IsPrime(n) and IsPrime(n+2));  # Muniru A Asiru, Feb 02 2018
  • Magma
    [p: p in PrimesUpTo(7000) | IsPrime(p+2) and p mod 30 eq 29 ]; // Vincenzo Librandi, Feb 13 2017
    
  • Maple
    isA060229 := proc(n)
        if modp(n+1,30) =0 and isprime(n) and isprime(n+2) then
            true;
        else
            false;
        end if;
    end proc:
    A060229 := proc(n)
        option remember;
        if n =1 then
            29;
        else
            for a from procname(n-1)+2 by 2 do
                if isA060229(a) then
                    return a;
                end if;
            end do:
        end if;
    end proc:
    seq(A060229(n),n=1..80) ; # R. J. Mathar, Feb 19 2017
  • Mathematica
    Select[Prime@ Range[10^3], PrimeQ[# + 2] && Mod[# + 1, 30] == 0 &] (* Michael De Vlieger, Jul 14 2016 *)
  • PARI
    isok(n) = isprime(n) && isprime(n+2) && !((n+1) % 30); \\ Michel Marcus, Dec 11 2013
    

Extensions

Minor edits by Ray Chandler, Apr 02 2009