A375545 Indices of the Sylvester primes (A375543) in the primes (A000040).

1, 2, 4, 14, 6, 34, 101, 111, 174, 42, 300, 21, 340, 3238, 1652, 2049, 3345, 5354, 6676, 7322, 12037, 30205, 51733, 7357, 99091, 167580, 2967, 15042, 2354, 193, 25884, 126695, 232179, 234477, 11370, 37546, 176867, 28678, 3270, 578, 84666, 966, 284, 349823, 2645

Offset

1,2

Links

Table of n, a(n) for n=1..45.

Formula

a(n) = A000720(A375543(n)).

Example

a(7) = 101 because A375543(7) = 547 = A000040(101).

Mathematica

Module[{nmax = 20, a = {}, p = 1, f}, Do[p *= p + 1; f = 2; While[MemberQ[a, f] || !Divisible[p, f], f = NextPrime[f]]; AppendTo[a, f], nmax]; PrimePi[a]] (* Paolo Xausa, Sep 09 2024 *)

Crossrefs

Cf. A000040, A000720, A375543.

Sequence in context: A369606 A325117 A193232 * A336841 A189486 A131758

Adjacent sequences: A375542 A375543 A375544 * A375546 A375547 A375548

Keyword

nonn

Author

Peter Luschny, Sep 05 2024

Extensions

More terms from Jinyuan Wang, Jul 25 2025

Status

approved