cp's OEIS Frontend

A037403 Numbers k such that every base-7 digit of k is a base-9 digit of k.

%I A037403 #15 Aug 05 2021 07:02:09
%S A037403 1,2,3,4,5,6,31,99,106,107,195,198,248,257,284,297,321,498,514,749,
%T A037403 750,751,758,767,785,936,939,940,943,950,968,996,1028,1086,1088,1110,
%U A037403 1163,1200,1218,1254,1453,1471,1498,1500,1502,1507
%N A037403 Numbers k such that every base-7 digit of k is a base-9 digit of k.
%H A037403 Reinhard Zumkeller, <a href="/A037403/b037403.txt">Table of n, a(n) for n = 1..10000</a>
%o A037403 (Haskell)
%o A037403 import Data.List ((\\), nub)
%o A037403 a037403 n = a037403_list !! (n-1)
%o A037403 a037403_list = filter f [1..] where
%o A037403    f x = null $ nub (ds 7 x) \\ nub (ds 9 x)
%o A037403    ds b x = if x > 0 then d : ds b x' else []  where (x', d) = divMod x b
%o A037403 -- _Reinhard Zumkeller_, May 30 2013
%Y A037403 Cf. A007093, A007095.
%Y A037403 Cf. A037402, A037404.
%K A037403 nonn,base
%O A037403 1,2
%A A037403 _Clark Kimberling_