A102490 Numbers in base-16 representation that cannot be written with decimal digits.

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

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

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

Adjacent sequences: A102487 A102488 A102489 * A102491 A102492 A102493

Keyword

nonn,base

Author

Reinhard Zumkeller, Jan 12 2005

Status

approved