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 1-3 of 3 results.

A237438 Double Hex-primes: let f(n) = A102489(n); then sequence lists primes p such that f(p) and f(f(p)) are also primes.

Original entry on oeis.org

2, 3, 5, 7, 11, 43, 47, 53, 59, 61, 89, 97, 101, 139, 151, 167, 199, 241, 251, 257, 269, 281, 337, 373, 443, 557, 599, 607, 647, 653, 829, 971, 1051, 1093, 1163, 1223, 1279, 1327, 1433, 1459, 1499, 1549, 1583, 1597, 1607
Offset: 1

Views

Author

Andreas Boe, Feb 07 2014

Keywords

Comments

This sequence is a subset of A103144.

Examples

			Dec61=prime -> Hex61=Dec97=prime -> Hex97=Dec151=prime.
		

Crossrefs

Cf. A102489.
Cf. A103144 (Hex-primes), A237439 (Triple Hex-primes), A237440 (Quadruple Hex-primes), A237441 (Quintuple Hex-primes).

A237439 Triple Hex-primes: let f(n) = A102489(n); then sequence lists primes p such that f(p), f(f(p)) and f(f(f(p))) are also primes.

Original entry on oeis.org

2, 3, 5, 7, 59, 61, 97, 101, 151, 257, 599, 647, 829, 1163, 1499, 1999, 2351, 2467, 2531, 2897, 2903, 3001, 3373, 4783, 4813, 5683, 6317, 6857, 6997, 7759, 8563, 8837, 8963, 9203, 9463, 9497, 9521, 10903, 10957
Offset: 1

Views

Author

Andreas Boe, Feb 07 2014

Keywords

Comments

The sequence is a subset of OEIS sequences A103144 and A237438

Examples

			Dec61=prime -> Hex61=Dec97=prime -> Hex97=Dec 151=prime -> Hex151=Dec337=prime
		

References

  • Original research by OEIS contributor Andreas Boe, Feb 2014

Crossrefs

Cf. A103144(Hex-primes), A237438 (Double Hex-primes), A237440 (Quadruple Hex-primes), A237441 (Quintuple Hex-primes)

A237441 Quintuple Hex-primes: let f(n) = A102489(n); then sequence lists primes p such that f(p), f(f(p)), f(f(f(p))), f(f(f(f(p)))) and f(f(f(f(f(p))))) are also primes.

Original entry on oeis.org

2, 3, 5, 7, 61, 101, 196853, 516151, 548239, 568627, 595039, 603833, 648887, 1996223, 2086907, 2487227, 3322757, 3711343, 4385137, 5226049, 5288929, 5853241, 8792039, 8796187, 8982191, 10203203, 12640297, 12664129, 12845561, 13156267, 13437481, 14342431
Offset: 1

Views

Author

Andreas Boe, Feb 07 2014

Keywords

Comments

The sequence is a subset of A103144, A237438, A237439 and A237440

Examples

			Dec61=prime -> Hex61=Dec97=prime -> Hex97=Dec151=prime -> Hex151=Dec337=prime -> Hex337=Dec823=prime -> Hex823=Dec2083=prime.
		

Crossrefs

Cf. A103144(Hex-primes), A237438(Double Hex-primes), A237439(Triple Hex-primes), A237440(Quadruple Hex-primes).

Programs

  • PARI
    hd(n) = my(d = digits(n)); sum(i=1, #d, 16^(i-1)*d[#d-i+1]);
    isok(p) = isprime(p) && isprime(p=hd(p)) && isprime(p=hd(p)) && isprime(p=hd(p)) && isprime(p=hd(p)) && isprime(p=hd(p)); \\ Michel Marcus, Feb 08 2014

Extensions

More terms from Michel Marcus, Feb 08 2014
Showing 1-3 of 3 results.