A176363 Non-semiprime numbers of order 2.

1, 2, 3, 7, 11, 12, 17, 18, 19, 24, 27, 28, 29, 30, 36, 37, 42, 43, 44, 45, 47, 48, 54, 56, 61, 63, 64, 66, 67, 68, 71, 72, 75, 78, 79, 80, 83, 89, 90, 92, 97, 98, 100, 101, 102, 104, 105, 107, 108, 110, 112, 114, 116, 117, 120, 125, 126, 131, 132, 135, 137, 144, 147, 148

Offset

1,2

Comments

Non-semiprimes with non-semiprime subscripts (or indices).

Links

Table of n, a(n) for n=1..64.

Formula

a(n) = A100959(A100959(n)).

Maple

A100959 := proc(n) option remember; if n = 1 then 1; else for a from procname(n-1)+1 do if numtheory[bigomega](a) <> 2 then return a; end if; end do end if; end proc: A176363 := proc(n) A100959(A100959(n)) ; end proc: seq(A176363(n), n=1..80) ; # R. J. Mathar, Apr 25 2010

Crossrefs

Sequence in context: A348745 A110449 A229082 * A067991 A114600 A088905

Adjacent sequences: A176360 A176361 A176362 * A176364 A176365 A176366

Keyword

nonn

Author

Juri-Stepan Gerasimov, Apr 16 2010

Extensions

Corrected (66 inserted) R. J. Mathar, Apr 25 2010

Status

approved