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.

A243630 Primes p such that 2*p^3 - 3 is also prime.

Original entry on oeis.org

2, 7, 11, 13, 47, 101, 107, 151, 163, 167, 251, 257, 401, 443, 467, 521, 571, 641, 653, 673, 797, 907, 911, 971, 983, 997, 1013, 1151, 1153, 1181, 1187, 1223, 1231, 1277, 1291, 1303, 1361, 1433, 1481, 1511, 1597, 1637, 1723, 1741, 1811, 1951, 2027, 2081, 2083, 2141, 2287, 2311
Offset: 1

Views

Author

Vincenzo Librandi, Jun 08 2014

Keywords

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(2500) | IsPrime(2*p^3 - 3)];
  • Mathematica
    Select[Prime[Range[2500]], PrimeQ[2 #^3 - 3] &]

A252042 Primes p such that 2*p^3 + 1 and 2*p^3 + 3 are also primes.

Original entry on oeis.org

2, 29, 1709, 5849, 6857, 6959, 8999, 10139, 11909, 13127, 13877, 15077, 15749, 17657, 19457, 23357, 23399, 26729, 27407, 27479, 28349, 30047, 31907, 32957, 39569, 46559, 46589, 46817, 50417, 58757, 59219, 60737, 62207, 62687, 62819, 66947, 70589, 71237, 74699
Offset: 1

Views

Author

K. D. Bajpai, Dec 13 2014

Keywords

Examples

			a(2) = 29 is prime: 2*29^3 + 1 = 48779 and 2*29^3 + 3 = 48781 are both primes.
a(3) = 1709 is prime: 2*1709^3 + 1 = 9982887659 and 2*1709^3 + 3 = 9982887661 are both primes.
		

Crossrefs

Programs

  • Mathematica
    Select[Prime[Range[10000]], And[PrimeQ[2*#^3 + 1], PrimeQ[2*#^3 + 3]] &]
    Select[Prime[Range[7500]],AllTrue[2#^3+{1,3},PrimeQ]&] (* Harvey P. Dale, Apr 03 2023 *)
  • PARI
    s=[]; forprime(p=2, 10^5, if(isprime(2*p^3 + 1) && isprime(2*p^3 + 3), s=concat(s, p))); s
Showing 1-2 of 2 results.