OFFSET
1,2
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
MATHEMATICA
Select[Range[600], Complement[IntegerDigits[#, 4], IntegerDigits[#, 7]]=={}&] (* Harvey P. Dale, Jan 25 2024 *)
PROG
(Haskell)
import Data.List ((\\), nub)
a037389 n = a037389_list !! (n-1)
a037389_list = filter f [1..] where
f x = null $ nub (ds 4 x) \\ nub (ds 7 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
KEYWORD
nonn,base
AUTHOR
STATUS
approved