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 A132960 #10 Sep 29 2017 02:49:38
%S A132960 1,0,3,2,25,94,721,3674,42561,291248,3628801,34254604,479001601,
%T A132960 5337581534,88966701825,1140807642974,20922789888001,321094542593824,
%U A132960 6402373705728001,109338195253235948,2457732174030848001
%N A132960 a(n) = n!*Sum_{d|n} (-1)^(d+1)/(d!*(n/d)^d).
%H A132960 G. C. Greubel, <a href="/A132960/b132960.txt">Table of n, a(n) for n = 1..450</a>
%F A132960 E.g.f.: Sum_{k>0}(1-exp(-x^k/k)).
%t A132960 Rest[ Range[0, 22]! CoefficientList[ Series[ - Sum[ Exp[ -x^k/k], {k, 25}], {x, 0, 22}], x]] (* _Robert G. Wilson v_, Sep 13 2007 *)
%o A132960 (PARI) a(n) = n!*sumdiv(n, d, (-1)^(d+1)/(d!*(n/d)^d)); \\ _Michel Marcus_, Sep 29 2017
%Y A132960 Cf. A005225, A132958, A132959, A132961, A132962, A132963.
%K A132960 easy,nonn
%O A132960 1,3
%A A132960 _Vladeta Jovovic_, Sep 06 2007
%E A132960 More terms from _Robert G. Wilson v_, Sep 13 2007