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.

A358179 Prime numbers with prime indices in A333244.

Original entry on oeis.org

31, 709, 1787, 8527, 19577, 27457, 42043, 52711, 72727, 96797, 112129, 137077, 167449, 173867, 239489, 250751, 285191, 352007, 401519, 443419, 464939, 490643, 527623, 683873, 718807, 755387, 839483, 864013, 985151, 1021271, 1080923, 1128889, 1159901, 1278779, 1323503, 1342907, 1656649, 1693031
Offset: 1

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Author

Michael P. May, Nov 11 2022

Keywords

Comments

This sequence can also be generated by the N-sieve.

Examples

			a(1) = prime(A333244(1)) = prime(11) = 31.
		

Crossrefs

Programs

  • Mathematica
    b[n_] := b[n] = If[PrimeQ[n], 1+b[PrimePi[n]], 0];
    a[n_] := a[n] = Module[{p}, p = If[n==1, 1, a[n-1]]; While[True, p = NextPrime[p]; If[#>3 && OddQ[#]&[b[p]], Break[]]]; p];
    Array[a, 50]
  • PARI
    b(n)={my(k=0); while(isprime(n), k++; n=primepi(n)); k};
    apply(x->prime(prime(prime(prime(x)))), select(n->b(n)%2, [1..500])) \\ Michel Marcus, Nov 18 2022

Formula

a(n) = prime(A333244(n)).
a(n) = A049090(A333242(n)).
a(n) = A038580(A262275(n)).
a(n) = A006450(A333243(n)).