1,1

A165560(a(n)) = 1; A003415(a(n)) mod 2 = 1;

A007814(a(n)) <= 1, A006519(a(n)) <= 2.

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

n is in this sequence iff either n is congruent to 2 modulo 4 or n and Omega(n) are both odd. - Charlie Neder, Feb 25 2019

(Haskell)

a235991 n = a235991_list !! (n-1)

a235991_list = filter (odd . a003415) [0..]

Cf. A003415, A006519, A007814, A165560, A235992 (complement), A000040 (subsequence).

Sequence in context: A293427 A293430 A087006 * A325362 A325396 A326533

Adjacent sequences: A235988 A235989 A235990 * A235992 A235993 A235994

nonn

Reinhard Zumkeller, Mar 11 2014

approved