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

%I A102490 #17 Feb 16 2025 08:32:55
%S A102490 10,11,12,13,14,15,26,27,28,29,30,31,42,43,44,45,46,47,58,59,60,61,62,
%T A102490 63,74,75,76,77,78,79,90,91,92,93,94,95,106,107,108,109,110,111,122,
%U A102490 123,124,125,126,127,138,139,140,141,142,143,154,155,156,157,158,159,160
%N A102490 Numbers in base-16 representation that cannot be written with decimal digits.
%H A102490 Reinhard Zumkeller, <a href="/A102490/b102490.txt">Table of n, a(n) for n = 1..10000</a>
%H A102490 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Hexadecimal.html">Hexadecimal</a>
%H A102490 Wikipedia, <a href="http://en.wikipedia.org/wiki/Hexadecimal">Hexadecimal</a>
%e A102490 42 = 2*16^1 + 10*16^0 = '2A', therefore 42 is a term.
%t A102490 Select[Range[200],IntegerLength[Max[IntegerDigits[#,16]]]>1&] (* _Harvey P. Dale_, Jun 12 2020 *)
%o A102490 (Haskell)
%o A102490 import Data.List (unfoldr)
%o A102490 a102490 n = a102490_list !! (n-1)
%o A102490 a102490_list = filter (any (> 9) . unfoldr
%o A102490    (\x -> if x == 0 then Nothing else Just $ swap $ divMod x 16)) [0..]
%o A102490 -- _Reinhard Zumkeller_, Jun 27 2013
%o A102490 (Python)
%o A102490 def ok(n): return any(hd > '9' for hd in hex(n)[2:])
%o A102490 print(list(filter(ok, range(161)))) # _Michael S. Branicky_, Oct 11 2021
%Y A102490 Complement of A102489; A102488, A102492, A102494.
%K A102490 nonn,base
%O A102490 1,1
%A A102490 _Reinhard Zumkeller_, Jan 12 2005