A037373 Positive numbers k such that every base-2 digit of k is a base-4 digit of k.

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

Offset

1,2

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

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

Cf. A037372, A037374, A037375, A037376, A037377, A037378, A037379.

Sequence in context: A166669 A286701 A077582 * A310928 A018887 A059014

Adjacent sequences: A037370 A037371 A037372 * A037374 A037375 A037376

Keyword

nonn,base

Author

Clark Kimberling

Status

approved