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Numbers whose base-3 digits are all present among their base-4 digits.
7

%I #18 Jun 20 2021 15:14:07

%S 1,2,4,8,13,18,22,24,25,26,28,33,36,41,56,66,70,72,73,74,75,78,81,82,

%T 84,88,96,97,98,99,100,104,108,112,114,120,121,122,129,132,133,134,

%U 135,137,141,144,145,146,147,148,149,151,152,156,157,158,161,162,164

%N Numbers whose base-3 digits are all present among their base-4 digits.

%H Reinhard Zumkeller, <a href="/A037380/b037380.txt">Table of n, a(n) for n = 1..10000</a>

%p q:= n-> (f-> is({}=f(3) minus f(4)))({k-> convert(n, base, k)[]}):

%p select(q, [$1..200])[]; # _Alois P. Heinz_, Jun 20 2021

%t Select[Range[200],SubsetQ[IntegerDigits[#,4],IntegerDigits[#,3]]&] (* _Harvey P. Dale_, Jan 19 2016 *)

%o (Haskell)

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

%o a037380 n = a037380_list !! (n-1)

%o a037380_list = filter f [1..] where

%o f x = null $ nub (ds 3 x) \\ nub (ds 4 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. A037381, A037382, A037383, A037384, A037385, A037386.

%K nonn,base

%O 1,2

%A _Clark Kimberling_