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A108218 Numbers of the form (11^i)*(12^j), with i, j >= 0.

%I A108218 #10 Mar 30 2025 03:13:57
%S A108218 1,11,12,121,132,144,1331,1452,1584,1728,14641,15972,17424,19008,
%T A108218 20736,161051,175692,191664,209088,228096,248832,1771561,1932612,
%U A108218 2108304,2299968,2509056,2737152,2985984,19487171,21258732,23191344,25299648
%N A108218 Numbers of the form (11^i)*(12^j), with i, j >= 0.
%H A108218 Reinhard Zumkeller, <a href="/A108218/b108218.txt">Table of n, a(n) for n = 1..10000</a>
%F A108218 Sum_{n>=1} 1/a(n) = 6/5. - _Amiram Eldar_, Mar 29 2025
%t A108218 With[{max = 3*10^7}, Flatten[Table[11^i*12^j, {i, 0, Log[11, max]}, {j, 0, Log[12, max/11^i]}]] // Sort] (* _Amiram Eldar_, Mar 29 2025 *)
%o A108218 (Haskell)
%o A108218 import Data.Set (singleton, deleteFindMin, insert)
%o A108218 a108218 n = a108218_list !! (n-1)
%o A108218 a108218_list = f $ singleton (1,0,0) where
%o A108218    f s = y : f (insert (11 * y, i + 1, j) $ insert (12 * y, i, j + 1) s')
%o A108218          where ((y, i, j), s') = deleteFindMin s
%o A108218 -- _Reinhard Zumkeller_, May 15 2015
%Y A108218 Cf. A003596, A003597, A107988, A003598, A108201, A108698, A064476, A003599, A108238, A107788, A108687, A108779, A108090, A108771.
%K A108218 nonn,easy
%O A108218 1,2
%A A108218 Douglas Winston (douglas.winston(AT)srupc.com), Jun 28 2005