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.

A356833 Primes p such that the minimum number of divisors among the numbers between p and NextPrime(p) is a square.

Original entry on oeis.org

5, 13, 19, 31, 37, 43, 53, 61, 67, 73, 79, 83, 89, 103, 109, 127, 131, 139, 151, 157, 163, 173, 181, 193, 199, 211, 223, 233, 241, 251, 257, 263, 269, 271, 277, 293, 307, 311, 313, 317, 331, 337, 353, 367, 373, 379, 383, 389, 397, 401, 409, 421, 433, 443, 449, 457, 461, 463, 467, 479
Offset: 1

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Author

Claude H. R. Dequatre, Sep 16 2022

Keywords

Examples

			13 is a term because up to the next prime 17, tau(14) = 4, tau(15) = 4, tau(16) = 5, thus the smallest tau(k) is 4 and 4 is a square (2^2).
23 is prime but not a term because up to the next prime 29, tau(24) = 8, tau(25) = 3, tau(26) = 4, tau(27) = 4, tau(28) = 6, thus the smallest tau(k) = 3 and 3 is not a square.
		

Crossrefs

Programs

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