A089229 Neither primes nor square numbers.

6, 8, 10, 12, 14, 15, 18, 20, 21, 22, 24, 26, 27, 28, 30, 32, 33, 34, 35, 38, 39, 40, 42, 44, 45, 46, 48, 50, 51, 52, 54, 55, 56, 57, 58, 60, 62, 63, 65, 66, 68, 69, 70, 72, 74, 75, 76, 77, 78, 80, 82, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 98, 99, 102, 104, 105, 106

Offset

1,1

Comments

Also, composites with an even number of divisors. - Juri-Stepan Gerasimov, Jul 17 2009

Links

Zak Seidov, Table of n, a(n) for n = 1..8671

Formula

(1 - A010051(a(n))) * (1 - A010052(a(n))) = 1. - Reinhard Zumkeller, Jul 07 2014

Mathematica

m=100; Complement[Range[0, m^2], Range[0, m]^2, Prime[Range[PrimePi[m^2]]]] (* Zak Seidov, Dec 12 2011*)

Prog

(Haskell)
a089229 n = a089229_list !! (n-1)
a089229_list = f a018252_list $ tail a000290_list where
   f (u:us) vs'@(v:vs) = if u < v then u : f us vs' else f us vs
-- Reinhard Zumkeller, Jul 07 2014
(PARI) lista(nn) = for (n=1, nn, if (!issquare(n) && !isprime(n), print1(n, ", "))); \\ Michel Marcus, Jun 01 2015
(PARI) is(n)=!issquare(n) && !isprime(n) \\ Charles R Greathouse IV, Oct 19 2015
(Magma) [n: n in [1..200] | not IsSquare(n) and not IsPrime(n)]; // Vincenzo Librandi, Jun 14 2016

Crossrefs

Complement of A089237.

Cf. A010051, A010052, A018252, A000290.

Sequence in context: A050199 A268388 A139118 * A345945 A123240 A131181

Adjacent sequences: A089226 A089227 A089228 * A089230 A089231 A089232

Keyword

nonn

Author

Roger L. Bagula, Dec 10 2003

Status

approved