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

Author

Reinhard Zumkeller, Jan 12 2005

Keywords

• nonn
• base

Examples

			42 = 2*16^1 + 10*16^0 = '2A', therefore 42 is a term.
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
• Eric Weisstein's World of Mathematics, Hexadecimal
• Wikipedia, Hexadecimal

Crossrefs

Complement of A102489; A102488, A102492, A102494.

Programs

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

Mathematica

Select[Range[200],IntegerLength[Max[IntegerDigits[#,16]]]>1&] (* Harvey P. Dale, Jun 12 2020 *)

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