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.

Showing 1-2 of 2 results.

A057324 First member of a prime triple in a p^2 + p - 1 progression.

Original entry on oeis.org

2, 3, 11, 13, 53, 131, 233, 241, 281, 569, 659, 691, 761, 881, 1693, 2063, 2411, 2521, 2551, 2663, 2729, 2741, 2861, 3089, 4021, 4159, 4201, 4243, 4423, 4793, 6091, 7103, 7229, 7369, 7753, 7829, 8053, 8641, 8669, 9041, 9059, 9539, 9649, 9769, 10513
Offset: 1

Views

Author

Patrick De Geest, Aug 15 2000

Keywords

Comments

There exist no such triples of the form p^2 + p + 1 because each third member is always divisible by 3.
Subsequence of A053184. - Pierre CAMI, Sep 13 2013

Examples

			2 -> 2^2+2-1 = 5 -> 5^2+5-1 = 29 hence the prime triple (2,5,29).
		

Crossrefs

Programs

  • Mathematica
    fmpQ[n_]:=AllTrue[NestList[#^2+#-1&,n,2],PrimeQ]; Select[Prime[Range[ 1300]],fmpQ] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jul 08 2019 *)
  • PARI
    is(n)=for(k=1,3,if(!isprime(n),return(0));n=n^2+n-1);1 \\ Charles R Greathouse IV, Sep 13 2013

A229092 First member of a prime 5-tuple in a p^2+p-1 progression.

Original entry on oeis.org

3, 20963909, 45608209, 46939069, 57856709, 73805093, 83307563, 83983931, 89836889, 90151643, 95786459, 98527859, 98886679, 116260099, 118084559, 118955549, 153404593, 155710213, 190926341, 204854891, 221010899, 238175309, 271884073, 295874083, 299614369
Offset: 1

Views

Author

Pierre CAMI, Sep 13 2013

Keywords

Comments

Subsequence of A057325.

Crossrefs

Programs

  • Mathematica
    pqQ[p_]:=AllTrue[Rest[NestList[#^2+#-1&,p,4]],PrimeQ]; Select[Prime[ Range[ 16232600]],pqQ] (* Harvey P. Dale, Oct 16 2021 *)
  • PARI
    is(n)=for(k=1,5,if(!isprime(n),return(0));n=n^2+n-1);1 \\ Charles R Greathouse IV, Sep 13 2013
Showing 1-2 of 2 results.