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A045051 Numbers whose base-4 representation contains exactly two 0's and four 2's. 1

%I #18 May 28 2023 01:39:32

%S 2090,2186,2210,2216,2570,2594,2600,2690,2696,2720,4266,4650,4746,

%T 4770,4776,6186,6282,6306,6312,6666,6690,6696,6786,6792,6816,8298,

%U 8346,8358,8361,8363,8366,8378,8426,8490,8586,8610

%N Numbers whose base-4 representation contains exactly two 0's and four 2's.

%H Enrique Pérez Herrero, <a href="/A045051/b045051.txt">Table of n, a(n) for n = 1..60000</a>

%t Select[Range[4^4, 4^7], {#4, #2} == {2, 4} & @@ DigitCount[#, 4] &] (* _Michael De Vlieger_, Dec 03 2017 *)

%o (Python)

%o import numpy as np

%o for a in range(10000):

%o x = np.base_repr(a, base=4)

%o if(x.count("0") == 2 and x.count("2") == 4):

%o print(a)

%o # _Enrique Pérez Herrero_, Dec 03 2017

%Y Cf. A007090.

%K nonn,base

%O 1,1

%A _Clark Kimberling_

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Last modified July 24 20:30 EDT 2024. Contains 374585 sequences. (Running on oeis4.)