A175248 Noncomposites (A008578) with noncomposite (A008578) subscripts.

1, 2, 3, 7, 13, 29, 37, 53, 61, 79, 107, 113, 151, 173, 181, 199, 239, 271, 281, 317, 349, 359, 397, 421, 457, 503, 541, 557, 577, 593, 613, 701, 733, 769, 787, 857, 863, 911, 953, 983, 1021, 1061, 1069, 1151, 1163, 1193, 1213, 1291, 1399, 1429, 1439, 1459

Offset

1,2

Comments

Noncomposite numbers of order 2.

a(n) = noncomposite(noncomposite(n)) = A008578(A008578(n)). a(1) = 1, a(n) = A055003(n) for n >=2. a(n) U A175249(n+1) = A008578 for n >= 1.

Links

Table of n, a(n) for n=1..52.

Formula

a(n)=A008578(A008578(n)).

Example

a(5) = 13 because a(5) = q(q(5)) = q(7) = 13, q = noncomposite.

Crossrefs

Cf. A006450, A102615.

Sequence in context: A074129 A233042 A055003 * A099361 A234003 A233350

Adjacent sequences: A175245 A175246 A175247 * A175249 A175250 A175251

Keyword

nonn

Author

Jaroslav Krizek, Mar 13 2010

Extensions

More terms from Juri-Stepan Gerasimov, Apr 15 2010

Edited by N. J. A. Sloane, Apr 21 2010 at the suggestion of R. J. Mathar

Status

approved