%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
