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A102490
Numbers in base-16 representation that cannot be written with decimal digits.
6
10, 11, 12, 13, 14, 15, 26, 27, 28, 29, 30, 31, 42, 43, 44, 45, 46, 47, 58, 59, 60, 61, 62, 63, 74, 75, 76, 77, 78, 79, 90, 91, 92, 93, 94, 95, 106, 107, 108, 109, 110, 111, 122, 123, 124, 125, 126, 127, 138, 139, 140, 141, 142, 143, 154, 155, 156, 157, 158, 159, 160
OFFSET
1,1
LINKS
Eric Weisstein's World of Mathematics, Hexadecimal
Wikipedia, Hexadecimal
EXAMPLE
42 = 2*16^1 + 10*16^0 = '2A', therefore 42 is a term.
MATHEMATICA
Select[Range[200], IntegerLength[Max[IntegerDigits[#, 16]]]>1&] (* Harvey P. Dale, Jun 12 2020 *)
PROG
(Haskell)
import Data.List (unfoldr)
a102490 n = a102490_list !! (n-1)
a102490_list = filter (any (> 9) . unfoldr
(\x -> if x == 0 then Nothing else Just $ swap $ divMod x 16)) [0..]
-- Reinhard Zumkeller, Jun 27 2013
(Python)
def ok(n): return any(hd > '9' for hd in hex(n)[2:])
print(list(filter(ok, range(161)))) # Michael S. Branicky, Oct 11 2021
CROSSREFS
Complement of A102489; A102488, A102492, A102494.
Sequence in context: A173688 A008709 A008708 * A057947 A228774 A073527
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Jan 12 2005
STATUS
approved