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A037385
Numbers k such that every base-3 digit of k is a base-9 digit of k.
7
1, 2, 9, 13, 18, 26, 81, 82, 83, 84, 85, 90, 99, 108, 117, 121, 162, 163, 164, 168, 170, 171, 180, 216, 234, 242, 244, 252, 325, 333, 488, 504, 650, 666, 729, 730, 731, 732, 733, 738, 739, 740, 741, 742, 747, 748, 749, 750, 751
OFFSET
1,2
LINKS
MATHEMATICA
Select[Range[1000], SubsetQ[IntegerDigits[#, 9], IntegerDigits[#, 3]]&] (* Harvey P. Dale, Dec 19 2015 *)
PROG
(Haskell)
import Data.List ((\\), nub)
a037385 n = a037385_list !! (n-1)
a037385_list = filter f [1..] where
f x = null $ nub (ds 3 x) \\ nub (ds 9 x)
ds b x = if x > 0 then d : ds b x' else [] where (x', d) = divMod x b
-- Reinhard Zumkeller, May 30 2013
KEYWORD
nonn,base
STATUS
approved