A247875 Numbers that are even or whose binary expansions contain one or more pairs of adjacent zeros when odd.

0, 2, 4, 6, 8, 9, 10, 12, 14, 16, 17, 18, 19, 20, 22, 24, 25, 26, 28, 30, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 44, 46, 48, 49, 50, 51, 52, 54, 56, 57, 58, 60, 62, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 86

Offset: 1

Author

Reinhard Zumkeller, Sep 25 2014

Keywords

• nonn

Comments

Complement of A247648; union of A004753 and A005843.

Links

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

Crossrefs

Cf. A247648, A004753, A005843.

Programs

Haskell

a247875 n = a247875_list !! (n-1)
a247875_list = filter (\x -> even x || f x) [0..] where
   f x = x > 0 && (x `mod` 4 == 0 || f (x `div` 2))

Mathematica

Module[{upto=100,odds},odds=Select[Range[1,upto,2], SequenceCount[ IntegerDigits[#,2],{0,0}]>0&];Sort[Join[odds,Range[0,upto,2]]]] (* The program uses the SequenceCount function from Mathematica version 10 *) (* Harvey P. Dale, Aug 30 2015 *)

Python

A247875_list = [n for n in range(10**3) if not n % 2 or '00' in bin(n)]
# Chai Wah Wu, Sep 26 2014

Extensions

Definition edited by Chai Wah Wu, Sep 26 2014

Definition clarified by Harvey P. Dale, Aug 30 2015