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A037373 Positive numbers k such that every base-2 digit of k is a base-4 digit of k. 8
1, 4, 7, 16, 17, 18, 19, 20, 24, 28, 31, 33, 36, 49, 52, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 88, 92, 96, 97, 98, 99, 100, 104, 108, 112, 113, 114, 115, 116, 120, 124, 127, 129, 132, 133, 134 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
PROG
(Haskell)
import Data.List ((\\), nub)
a037373 n = a037373_list !! (n-1)
a037373_list = filter f [1..] where
f x = null $ nub (ds 2 x) \\ nub (ds 4 x)
ds b x = if x > 0 then d : ds b x' else [] where (x', d) = divMod x b
-- Reinhard Zumkeller, May 30 2013
CROSSREFS
Sequence in context: A166669 A286701 A077582 * A310928 A018887 A059014
KEYWORD
nonn,base
AUTHOR
STATUS
approved

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Last modified February 26 11:31 EST 2024. Contains 370352 sequences. (Running on oeis4.)