A092206 Positive integers that are not of the form n^2 or 3n^2.

2, 5, 6, 7, 8, 10, 11, 13, 14, 15, 17, 18, 19, 20, 21, 22, 23, 24, 26, 28, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 76, 77, 78, 79, 80, 82, 83, 84

Offset: 1

Author

Eric W. Weisstein, Feb 24 2004

Keywords

• nonn

Comments

Values of n such that Q(sqrt(-n)) has 2 units.

A214295(a(n)) = 0. - Reinhard Zumkeller, Jul 12 2012

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
• Eric Weisstein's World of Mathematics, Unit

Crossrefs

Cf. A000290, A033428, A092205.

Programs

Haskell

a092206 n = a092206_list !! (n-1)
a092206_list = filter ((== 0) . a214295) [1..]
-- Reinhard Zumkeller, Jul 12 2012

Mathematica

Select[ Range[100], Not[ IntegerQ[ Sqrt[#] ] || IntegerQ[ Sqrt[#/3] ] ]&] (* Jean-François Alcover, Oct 30 2012 *)

PARI

is(n)=!issquare(n/3^valuation(n,3)) \\ Charles R Greathouse IV, Oct 30 2012