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%I #19 Sep 08 2022 08:46:19
%S 6,8,66,68,86,88,666,668,686,688,866,868,886,888,6666,6668,6686,6688,
%T 6866,6868,6886,6888,8666,8668,8686,8688,8866,8868,8886,8888,66666,
%U 66668,66686,66688,66866,66868,66886,66888,68666,68668,68686,68688,68866,68868
%N Numbers with digits 6 and 8 only.
%C All terms are even.
%F a(n) = 2 * A032834(n).
%t Table[FromDigits /@ Tuples[{6, 8}, n], {n, 5}] // Flatten (* or *)
%t Select[Range@ 70000, Total@ Pick[DigitCount@ #, {0, 0, 0, 0, 0, 1, 0, 1, 0, 0}, 0] == 0 &] (* _Michael De Vlieger_, Apr 02 2017 *)
%o (Magma) [n: n in [1..100000] | Set(IntegerToSequence(n, 10)) subset {6, 8}]
%o (Python)
%o def a(n): return int(bin(n+1)[3:].replace('0', '6').replace('1', '8'))
%o print([a(n) for n in range(1, 45)]) # _Michael S. Branicky_, Jun 08 2021
%Y Cf. A032834.
%Y Numbers n with digits 6 and k only for k = 0 - 5 and 7 - 9: A204093 (k = 0), A284293 (k = 1), A284632 (k = 2), A284633 (k = 3), A284634 (k = 4), A256291 (k = 5), A256292 (k = 7), this sequence (k = 8), A284636 (k = 9).
%K nonn,base
%O 1,1
%A _Jaroslav Krizek_, Apr 02 2017
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