This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A108748 #8 Sep 25 2020 05:48:34
%S A108748 1,9,13,81,117,169,729,1053,1521,2197,6561,9477,13689,19773,28561,
%T A108748 59049,85293,123201,177957,257049,371293,531441,767637,1108809,
%U A108748 1601613,2313441,3341637,4782969,4826809,6908733,9979281,14414517,20820969
%N A108748 Numbers of the form (9^i)*(13^j), with i, j >= 0.
%H A108748 Amiram Eldar, <a href="/A108748/b108748.txt">Table of n, a(n) for n = 1..10000</a>
%F A108748 Sum_{n>=1} 1/a(n) = (9*13)/((9-1)*(13-1)) = 39/32. - _Amiram Eldar_, Sep 25 2020
%F A108748 a(n) ~ exp(sqrt(2*log(9)*log(13)*n)) / sqrt(117). - _Vaclav Kotesovec_, Sep 25 2020
%t A108748 n = 10^6; Flatten[Table[9^i*13^j, {i, 0, Log[9, n]}, {j, 0, Log[13, n/9^i]}]] // Sort (* _Amiram Eldar_, Sep 25 2020 *)
%Y A108748 Cf. A025635, A108687, A107326, A107364, A107462, A107466, A107710, A108056, A107764, A108090.
%K A108748 nonn,easy
%O A108748 1,2
%A A108748 Douglas Winston (douglas.winston(AT)srupc.com), Jun 23 2005