A175247 Primes (A000040) with noncomposite (A008578) subscripts.

2, 3, 5, 11, 17, 31, 41, 59, 67, 83, 109, 127, 157, 179, 191, 211, 241, 277, 283, 331, 353, 367, 401, 431, 461, 509, 547, 563, 587, 599, 617, 709, 739, 773, 797, 859, 877, 919, 967, 991, 1031, 1063, 1087, 1153, 1171, 1201, 1217, 1297, 1409, 1433, 1447

Offset

1,1

Comments

A006450 is the main entry for these numbers. [Arkadiusz Wesolowski, Mar 12 2011]

Links

Paolo Xausa, Table of n, a(n) for n = 1..10000

Formula

a(n) U A007821(n+1) = A000040(n) for n >= 1.

a(n) = prime(noncomposite(n)) = A000040(A008578(n)).

a(1) = 2, a(n) = A006450(n-1) for n >= 2.

Example

a(5) = 17 because a(5) = p(q(5)) = p(7) = 17, p = prime, q = noncomposite.

Mathematica

Join[{2}, Prime[Prime[Range[50]]]] (* Paolo Xausa, Mar 27 2026 *)

Crossrefs

Cf. A006450, A000040.

Sequence in context: A055498 A395231 A258185 * A298598 A079370 A014210

Adjacent sequences: A175244 A175245 A175246 * A175248 A175249 A175250

Keyword

nonn,easy

Author

Jaroslav Krizek, Mar 13 2010

Status

approved