|
|
A037383
|
|
Numbers k such that every base-3 digit of k is a base-7 digit of k.
|
|
7
|
|
|
1, 2, 13, 51, 63, 67, 68, 79, 84, 91, 99, 105, 134, 205, 211, 246, 252, 345, 351, 352, 354, 355, 357, 358, 359, 360, 361, 362, 363, 364, 366, 373, 380, 387, 394, 401, 406, 441, 442, 443, 444, 445, 446, 447, 448, 449, 454, 455, 457
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
LINKS
|
|
|
MATHEMATICA
|
Select[Range[500], Complement[Union[IntegerDigits[#, 3]], Union[IntegerDigits[#, 7]]]=={}&] (* Harvey P. Dale, Jan 28 2024 *)
|
|
PROG
|
(Haskell)
import Data.List ((\\), nub)
a037383 n = a037383_list !! (n-1)
a037383_list = filter f [1..] where
f x = null $ nub (ds 3 x) \\ nub (ds 7 x)
ds b x = if x > 0 then d : ds b x' else [] where (x', d) = divMod x b
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,base
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|