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.

A066101 Duplicate of A063784.

Original entry on oeis.org

73, 757, 1772893, 48551233240513, 378890487846991, 3156404483062657, 17390284913300671, 280343912759041771, 319913861581383373, 487014306953858713, 7824668707707203971, 8443914727229480773, 32564717507686012813, 48095468363380957093, 54811417636756749151
Offset: 1

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Comments

Previous name: Primes of the form q = p^6 + p^3 + 1 = sigma_3(p^2), where p is prime.

Examples

			73 = 64 + 8 + 1, 757 = 729 + 27 + 1, etc.
		

A342691 Primes of the form (p^k)^2 + p^k + 1 with prime p and positive integer k.

Original entry on oeis.org

7, 13, 31, 73, 307, 757, 1723, 3541, 5113, 8011, 10303, 17293, 28057, 30103, 86143, 147073, 262657, 459007, 492103, 552793, 579883, 598303, 684757, 704761, 735307, 830833, 1191373, 1204507, 1353733, 1395943, 1424443, 1482307, 1772893, 1886503, 2037757, 2212657
Offset: 1

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Author

Martin Becker, May 18 2021

Keywords

Comments

Also, primes of the form (p^3^m)^2 + p^3^m + 1 with prime p and nonnegative integer m, since k must be a power of 3, from the theory of cyclotomic polynomials.

Examples

			31 = (5^1)^2 + 5^1 + 1 is in the sequence as 31 is prime and 5 is prime and 1 is a positive integer.
73 = (2^3)^2 + 2^3 + 1 is in the sequence as it is prime and 2 is prime and 3 is a positive integer.
		

Crossrefs

Contains A053183 and A063784.
Intersection of A335865 and A000040 minus {3}.

Programs

  • Mathematica
    Select[Table[q^2 + q + 1, {q, Select[Range[1500], PrimePowerQ[#] &]}], PrimeQ] (* Amiram Eldar, Aug 16 2024 *)
  • PARI
    for(q=2,2048,if(isprimepower(q),m=q^2+q+1;if(isprime(m),print1(m, ", "))))
Showing 1-2 of 2 results.