A272698 -id:A272698 - cp's OEIS frontend

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A272697 Powers of 2 with exactly one odd decimal digit.

Original entry on oeis.org

1, 16, 32, 128, 256, 1024, 4096, 262144, 524288, 8388608

Offset: 1

Seiichi Manyama, May 04 2016

Inspired by A068994 (Powers of 2 such that number of odd digits is 0).
No additional terms up to 2^10000.
No additional terms < 2^500000. - Chai Wah Wu, May 22 2016
No additional terms < 2^(10^10). - Michael S. Branicky, Apr 16 2023

Cf. A068994, A272698.

Select[2^Range[0, 50000], Total@ Pick[DigitCount@ #, {1, 0, 1, 0, 1, 0, 1, 0, 1, 0}, 1] == 1 &] (* Michael De Vlieger, May 04 2016 *)
od1Q[n_]:=Count[IntegerDigits[n],?(OddQ[#]&)]==1; Select[2^Range[0,100],od1Q] (* _Harvey P. Dale, Sep 04 2024 *)

ary = [1]
s = 1
(1..10 ** 4).each{|i|
  s *= 2
  j = s.to_s.split('').map(&:to_i).select{|i| i % 2 == 1}.size
  ary << s if j == 1
}
p ary

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