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 A113853 #16 Oct 13 2020 04:38:32
%S A113853 108,12500,84375,337500,3294172,22235661,88942644,2573571875,
%T A113853 10294287500,69486440625,277945762500,1141246682444,7703415106497,
%U A113853 30813660425988,891598970659375,1211500426369012,3566395882637500,8177627877990831,24073172207803125,32710511511963324
%N A113853 Numbers whose prime factors are raised to the powers of themselves.
%C A113853 Does not include A000312: Number of labeled mappings from n points to themselves (endofunctions): n^n.
%F A113853 Sum_{n>=1} 1/a(n) = Product_{p prime} (1 + 1/p^p) - Sum_{p prime} 1/p^p - 1 = 0.009354434361... - _Amiram Eldar_, Oct 13 2020
%e A113853 108 = 2^2*3^3. 2 is raised to the power of itself and 3 is raised to the power of itself.
%t A113853 p = Drop[Subsets@Prime@Range@7, 8]; Take[ Sort[Times @@@ (p^p)], 18] (* _Robert G. Wilson v_, Jan 26 2006 *)
%Y A113853 Cf. A000312, A048102, A051674, A094289.
%K A113853 easy,nonn
%O A113853 1,1
%A A113853 _Cino Hilliard_, Jan 25 2006
%E A113853 Corrected and extended by _Robert G. Wilson v_, Jan 26 2006
%E A113853 Offset corrected and more terms added by _Amiram Eldar_, Oct 13 2020