A158582 Numbers with at least two zeros in their binary representation.

4, 8, 9, 10, 12, 16, 17, 18, 19, 20, 21, 22, 24, 25, 26, 28, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 48, 49, 50, 51, 52, 53, 54, 56, 57, 58, 60, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91

Offset: 1

Author

Reinhard Zumkeller, Apr 16 2009

Keywords

• nonn

Comments

Subsequence of A158581; complement of A089633; A023416(a(n))>1.

A265705(a(n),k) != A265705(a(n),a(n)-k) for at least one k <= a(n). - Reinhard Zumkeller, Dec 15 2015

Links

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

Crossrefs

Cf. A007088, A023416.

Cf. A089633, A158581, A265705.

Programs

Haskell

a158582 n = a158582_list !! (n-1)
a158582_list = [x | x <- [0..], a023416 x > 1]
-- Reinhard Zumkeller, Mar 31 2015

Mathematica

Select[Range[100],DigitCount[#,2,0]>1&] (* Harvey P. Dale, Jan 19 2015 *)

Python

def A158582(n):
    def f(x):
        c = n+(((l:=(x+1).bit_length())+1)*(l-2)>>1)
        m = bin(x+1)[2:].find('0')
        c += m if m>-1 else l
        return c
    m, k = n, f(n)
    while m != k: m, k = k, f(k)
    return m # Chai Wah Wu, Dec 24 2024