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
Keywords
Examples
a(7) = 101 because A375543(7) = 547 = A000040(101).
Programs
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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 *)
Extensions
More terms from Jinyuan Wang, Jul 25 2025