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.

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A304292 Primes p such that p + q^2 + r^3 is also prime, where p, q and r are consecutive primes.

Original entry on oeis.org

31, 71, 79, 83, 89, 131, 137, 163, 179, 191, 251, 281, 331, 373, 401, 479, 569, 619, 659, 673, 701, 821, 881, 911, 929, 941, 947, 1093, 1291, 1301, 1373, 1409, 1459, 1481, 1559, 1583, 1657, 1811, 1907, 1973, 1987, 2003, 2089, 2243, 2309, 2339, 2341, 2357, 2423
Offset: 1

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Author

Paolo P. Lava, May 15 2018

Keywords

Comments

Similar to A259772 where the condition is p and p^3 + q^2 + r both prime.

Examples

			a(1) = 31 is prime and 31 + 37^2 + 41^3 = 70321 is prime too.
a(2) = 71 is prime and 71 + 73^2 + 79^3 = 498439 is prime too.
		

Crossrefs

Cf. A259772.

Programs

  • Maple
    select(n->isprime(n) and isprime(n+nextprime(n)^2+nextprime(nextprime(n))^3),[$1..2500]);
  • Mathematica
    Select[Partition[Prime@ Range@ 400, 3, 1], PrimeQ[#1 + #2^2 + #3^3] & @@ # &][[All, 1]] (* Michael De Vlieger, May 27 2018 *)

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.