A355967 Indices of the primes that occur in A104589.

1, 3, 6, 25, 104, 634, 1236, 22613, 103409, 929044, 6298419, 80396036, 843325558, 5843115733, 24428345613, 515211289906, 4021634909249, 77930896716918, 387592118891917, 53467625139656294

Offset

1,2

Links

Table of n, a(n) for n=1..20.

Example

The primes in A104589 are 2, 5, 13, 97, ... with prime indices 1, 3, 6, 25, ...

Mathematica

s[1] = 1; s[n_] := s[n] = s[n - 1] + Sum[If[CompositeQ[s[k]], 0, s[k]], {k, 1, n - 1}]; PrimePi[Select[s /@ Range[200], PrimeQ[#] &]] (* Amiram Eldar, Jul 21 2022 *)

Prog

(PARI) lista(nn) = my(last=1, s = 1, list = List()); for (n=2, nn, last += s; if (isprime(last), s += last; listput(list, primepi(last))); ); Vec(list);

Crossrefs

Cf. A000040, A000720, A104589, A355958.

Sequence in context: A266549 A057730 A350752 * A074432 A212650 A297572

Adjacent sequences: A355964 A355965 A355966 * A355968 A355969 A355970

Keyword

nonn,more

Author

Michel Marcus, Jul 21 2022

Extensions

a(14)-a(20) from Amiram Eldar, Jul 21 2022

Status

approved