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%I A108779 #11 Sep 25 2020 06:01:33
%S A108779 1,10,11,100,110,121,1000,1100,1210,1331,10000,11000,12100,13310,
%T A108779 14641,100000,110000,121000,133100,146410,161051,1000000,1100000,
%U A108779 1210000,1331000,1464100,1610510,1771561,10000000,11000000,12100000,13310000
%N A108779 Numbers of the form (10^i)*(11^j), with i, j >= 0.
%H A108779 Reinhard Zumkeller, <a href="/A108779/b108779.txt">Table of n, a(n) for n = 1..10000</a>
%F A108779 Sum_{n>=1} 1/a(n) = (10*11)/((10-1)*(11-1)) = 11/9. - _Amiram Eldar_, Sep 25 2020
%F A108779 a(n) ~ exp(sqrt(2*log(10)*log(11)*n)) / sqrt(110). - _Vaclav Kotesovec_, Sep 25 2020
%t A108779 n = 10^7; Flatten[Table[10^i*11^j, {i, 0, Log10[n]}, {j, 0, Log[11, n/10^i]}]] // Sort (* _Amiram Eldar_, Sep 25 2020 *)
%o A108779 (Haskell)
%o A108779 import Data.Set (singleton, deleteFindMin, insert)
%o A108779 a108779 n = a108779_list !! (n-1)
%o A108779 a108779_list = f $ singleton (1,0,0) where
%o A108779    f s = y : f (insert (10 * y, i + 1, j) $ insert (11 * y, i, j + 1) s')
%o A108779          where ((y, i, j), s') = deleteFindMin s
%o A108779 -- _Reinhard Zumkeller_, May 15 2015
%Y A108779 Cf. A025612, A025616, A025621, A025625, A025629, A025632, A025634, A025635, A108761, A003596, A003597, A107988, A003598, A108698, A003599, A107788, A108687, A108090.
%K A108779 nonn,easy
%O A108779 1,2
%A A108779 Douglas Winston (douglas.winston(AT)srupc.com), Jun 26 2005

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