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.

A345335 Primes p such that A014499(k) / A000120(k) is an integer, where k = A000720(p).

Original entry on oeis.org

2, 3, 5, 7, 19, 23, 29, 41, 53, 67, 71, 73, 83, 89, 97, 113, 131, 139, 193, 197, 211, 269, 281, 283, 311, 317, 337, 347, 349, 353, 359, 373, 389, 479, 503, 521, 523, 547, 563, 587, 593, 601, 647, 661, 691, 719, 739, 839, 857, 863, 881, 887, 929, 937, 983, 1013
Offset: 1

Views

Author

Ctibor O. Zizka, Jun 14 2021

Keywords

Comments

A014499(k) / A000120(k) = 1 gives A072439.

Examples

			prime(8) = 19, A014499(8)/A000120(8) = 3, thus 19 is a term.
		

Crossrefs

Programs

  • Maple
    R:= NULL: p:= 1: count:= 0:
    for n from 1 while count < 100 do
      p:= nextprime(p);
      if convert(convert(p,base,2),`+`) mod convert(convert(n,base,2),`+`) = 0 then R:= R,p; count:= count+1 fi;
    od:
    R; # Robert Israel, Apr 21 2025
  • Mathematica
    Select[Range[1000], PrimeQ[#] && Divisible @@ DigitCount[{#, PrimePi[#]}, 2, 1] &] (* Amiram Eldar, Jun 14 2021 *)
  • PARI
    isok(p) = isprime(p) && ((hammingweight(p) % hammingweight(primepi(p))) == 0); \\ Michel Marcus, Jun 14 2021