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 A060943 #25 Apr 09 2021 09:16:36 %S A060943 1,5,251,357904,25795462624,141727869124448256, %T A060943 83296040059942781485105152,7013444132843374500928464765799366656, %U A060943 109329825340451764123791003609208862665771818418176,396334659032531033249146049131230887376087800711479296000000000000 %N A060943 a(n) = n!^n * Sum_{k=1..n} 1/k^n. %H A060943 Harry J. Smith, <a href="/A060943/b060943.txt">Table of n, a(n) for n = 1..30</a> %F A060943 a(n) ~ 2^(n/2) * Pi^(n/2) * n^(n*(2*n+1)/2) / exp(n^2 - 1/12). - _Vaclav Kotesovec_, Aug 27 2017 %F A060943 a(n) = (n!)^n * [x^n] PolyLog(n,x)/(1 - x), where PolyLog() is the polylogarithm function. - _Ilya Gutkovskiy_, Nov 27 2017 %e A060943 a(3) = 6^3 *(1 + 1/2^3 + 1/3^3) = 251. %p A060943 A060943:= n-> (n!)^n*add(1/j^n, j=1..n); seq(A060943(n), n=1..15); # _G. C. Greubel_, Apr 09 2021 %t A060943 Table[(n!)^n * Sum[1/i^n, {i, 1, n}], {n, 1, 10}] (* _Vaclav Kotesovec_, Aug 27 2017 *) %o A060943 (PARI) { default(realprecision, 100); for (n=1, 30, write("b060943.txt", n, " ", n!^n * sum(k=1, n, 1/k^n)); ) } \\ _Harry J. Smith_, Jul 14 2009 %o A060943 (Magma) [(Factorial(n))^n*(&+[1/j^n: j in [1..n]]): n in [1..15]]; // _G. C. Greubel_, Apr 09 2021 %o A060943 (Sage) [(factorial(n))^n*sum(1/j^n for j in (1..n)) for n in (1..15)] # _G. C. Greubel_, Apr 09 2021 %Y A060943 Cf. A036740. %Y A060943 Main diagonal of A291556. %K A060943 easy,nonn %O A060943 1,2 %A A060943 _Leroy Quet_, May 07 2001