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.

A357170 Primes p such that the minimum number of divisors among the numbers between p and NextPrime(p) is a prime power.

Original entry on oeis.org

3, 5, 7, 13, 19, 23, 29, 31, 37, 41, 43, 47, 53, 61, 67, 73, 79, 83, 89, 101, 103, 109, 113, 127, 131, 137, 139, 151, 157, 163, 167, 173, 181, 193, 199, 211, 223, 229, 233, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 349, 353, 359, 367, 373
Offset: 1

Views

Author

Claude H. R. Dequatre, Sep 16 2022

Keywords

Examples

			19 is a term because up to the next prime 23, tau(20) = 6, tau(21) = 4, tau(22) = 4, thus the smallest tau(k) is 4 and 4 is a prime power (2^2).
97 is prime but not a term because up to the next prime 101, tau(98) = 6, tau(99) = 6, tau(100) = 9, thus the smallest tau(k) is 6 and 6 is not a prime power.
		

Crossrefs

Programs

  • PARI
    isok(p)=isprimepower(vecmin(apply(numdiv, [p+1..nextprime(p+1)-1])));
    forprime(p=3, 2000, if(isok(p), print1(p", ")))