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A284632 Numbers n with digits 2 and 6 only. 8

%I

%S 2,6,22,26,62,66,222,226,262,266,622,626,662,666,2222,2226,2262,2266,

%T 2622,2626,2662,2666,6222,6226,6262,6266,6622,6626,6662,6666,22222,

%U 22226,22262,22266,22622,22626,22662,22666,26222,26226,26262,26266,26622,26626

%N Numbers n with digits 2 and 6 only.

%C All terms are composite.

%F a(n) = 2 * A032917(n).

%t Table[Map[FromDigits, Tuples[{2, 6}, {k}]], {k, 5}] // Flatten (* _Michael De Vlieger_, Mar 30 2017 *)

%o (MAGMA) [n: n in [1..100000] | Set(IntegerToSequence(n, 10)) subset {2, 6}]

%Y Numbers n with digits 6 and k only for k = 0 - 5 and 7 - 9: A204093 (k = 0), A284293 (k = 1), this sequence (k = 2), A284633 (k = 3), A284634 (k = 4), A256291 (k = 5), A256292 (k = 7), A284635 (k = 8), A284636 (k = 9).

%K nonn,base

%O 1,1

%A _Jaroslav Krizek_, Mar 30 2017

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Last modified July 12 21:31 EDT 2020. Contains 335669 sequences. (Running on oeis4.)