A065858 m-th composite number c(m) = A002808(m), where m is the n-th prime number: a(n) = A002808(A000040(n)).

6, 8, 10, 14, 20, 22, 27, 30, 35, 44, 46, 54, 58, 62, 66, 75, 82, 85, 92, 96, 99, 108, 114, 120, 129, 134, 136, 142, 144, 148, 166, 171, 178, 182, 194, 196, 204, 210, 215, 221, 230, 232, 245, 247, 252, 254, 268, 285, 289, 291, 296, 302, 304, 318, 324, 330, 338

Offset

1,1

Comments

Composites (A002808) with prime (A000040) subscripts. a(n) U A175251(n) = A002808(n). Subsequence of A022449 (composites (A002808) with noncomposite (A008578) subscripts), a(n) = A022449(n+1). - Jaroslav Krizek, Mar 14 2010

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

P, C:= selectremove(isprime, [seq(i, i=2..10^3)]):
seq(C[P[i]], i=1..100); # Robert Israel, Mar 09 2025

Mathematica

Composite[n_] := FixedPoint[n + PrimePi[#] + 1 & , n + PrimePi[n] + 1];
a[n_] := Composite[Prime[n]];
Array[a, 100] (* Jean-François Alcover, Jan 26 2018, after Robert G. Wilson v *)

Crossrefs

Cf. A002808, A000040, A008578, A022449, A065856, A065857, A175251.

Sequence in context: A298252 A152126 A315853 * A243537 A073582 A363837

Adjacent sequences: A065855 A065856 A065857 * A065859 A065860 A065861

Keyword

nonn

Author

Labos Elemer, Nov 26 2001

Status

approved