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.

A259772 Primes p such that p^3 + q^2 + r is also prime, where p,q,r are consecutive primes.

Original entry on oeis.org

3, 17, 19, 43, 53, 89, 107, 149, 293, 401, 439, 449, 659, 809, 821, 937, 1009, 1031, 1091, 1097, 1123, 1163, 1181, 1259, 1277, 1367, 1427, 1657, 1721, 1777, 1789, 1811, 1987, 2027, 2063, 2207, 2333, 2417, 2503, 2657, 2713, 3067, 3079, 3083, 3251, 3389, 3491, 3527
Offset: 1

Views

Author

K. D. Bajpai, Jul 05 2015

Keywords

Examples

			a(2) = 17 is prime: 17^3 + 19^2 + 23 = 5297 which is also prime.
a(3) = 19 is prime: 19^3 + 23^2 + 29 = 7417 which is also prime.
		

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo (3000) | IsPrime(k) where k is (p^3 + NextPrime(p)^2 + NextPrime(NextPrime(p)))];
  • Maple
    select(n -> isprime(n) and isprime((n)^3+nextprime(n)^2+nextprime(nextprime((n)))), [seq(n, n=1..10000)]);
  • Mathematica
    Select[Prime[Range[1000]], PrimeQ[#^3 + NextPrime[#]^2 + NextPrime[NextPrime[#]]]&]
    Select[Partition[Prime[Range[500]],3,1],PrimeQ[#[[1]]^3+ #[[2]]^2+ #[[3]]]&][[All,1]] (* Harvey P. Dale, Dec 23 2021 *)
  • PARI
    forprime(p=1, 3000, q=nextprime(p+1); r=nextprime(q+1); k=(p^3 + q^2 + r); if(isprime(k), print1(p,", ")))
    

A348267 Primes of the form q^3+r^5+s^7, where q,r,s are consecutive primes.

Original entry on oeis.org

19504103, 410711297, 895293793, 19205982415663, 27139128435043, 122997897555661, 2351321783571193, 33026024797765183, 44544286011297461, 257023170905666323, 630639912549644209, 896737512757442999, 2267254920439040789, 2344105012311523369, 25786002910400593997
Offset: 1

Views

Author

Dumitru Damian, Oct 09 2021

Keywords

Comments

Exponent values (3,5,7) given by the prime triplet of the form p,p+2,p+4.

Examples

			19504103 is a term because 5^3+7^5+11^7 = 19504103 is prime;
410711297 is a term because 11^3+13^5+17^7 = 410711297 is prime.
		

Crossrefs

Programs

  • Mathematica
    Select[(#[[1]]^3 + #[[2]]^5 + #[[3]]^7) & /@ Partition[Select[Range[1000], PrimeQ], 3, 1], PrimeQ] (* Amiram Eldar, Oct 11 2021 *)
  • Sage
    def Q3R5S7(x):
        return Primes().unrank(x)^3+Primes().unrank(x+1)^5+Primes().unrank(x+2)^7
    A348267 = [Q3R5S7(x) for x in range(0,10^3) if Q3R5S7(x) in Primes()]
Showing 1-2 of 2 results.