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Numbers k such that every base-4 digit of k is a base-5 digit of k.
6

%I #16 Aug 04 2021 02:21:35

%S 1,2,3,5,10,15,21,28,37,38,42,58,63,76,80,86,132,136,137,138,142,152,

%T 160,167,178,183,190,191,202,204,205,210,213,214,215,217,220,221,222,

%U 223,238,240,256,257,258,261,266,276,277,278

%N Numbers k such that every base-4 digit of k is a base-5 digit of k.

%H Reinhard Zumkeller, <a href="/A037387/b037387.txt">Table of n, a(n) for n = 1..10000</a>

%t Select[Range[300],SubsetQ[IntegerDigits[#,5],IntegerDigits[#,4]]&] (* _Harvey P. Dale_, Mar 27 2019 *)

%o (Haskell)

%o import Data.List ((\\), nub)

%o a037387 n = a037387_list !! (n-1)

%o a037387_list = filter f [1..] where

%o f x = null $ nub (ds 4 x) \\ nub (ds 5 x)

%o ds b x = if x > 0 then d : ds b x' else [] where (x', d) = divMod x b

%o -- _Reinhard Zumkeller_, May 30 2013

%Y Cf. A007090, A007091.

%Y Cf. A037388, A037389, A037390, A037391, A037392.

%K nonn,base

%O 1,2

%A _Clark Kimberling_