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 A344430 #17 Apr 05 2023 15:07:51
%S A344430 1,-3,-30,-30,-3155,43501,-780042,-780042,-780042,9999219958,
%T A344430 -275312450653,-275312450653,-303150419042906,10808856406515110,
%U A344430 448702746787374485,448702746787374485,-826791559139549389692,-826791559139549389692
%N A344430 a(n) = Sum_{k=1..n} mu(k) * k^k.
%t A344430 a[n_] := Sum[MoebiusMu[k] * k^k, {k,1,n}]; Array[a, 20] (* _Amiram Eldar_, May 19 2021 *)
%t A344430 Accumulate[Table[MoebiusMu[n]n^n,{n,20}]] (* _Harvey P. Dale_, Jan 25 2022 *)
%o A344430 (PARI) a(n) = sum(k=1, n, moebius(k)*k^k);
%o A344430 (Python)
%o A344430 from sympy import mobius
%o A344430 def A344430(n): return sum(mobius(k)*k**k for k in range(1,n+1)) # _Chai Wah Wu_, Apr 05 2023
%Y A344430 Cf. A001923, A002321, A008683, A307653, A336276, A336277, A336278, A336279, A344429.
%K A344430 sign
%O A344430 1,2
%A A344430 _Seiichi Manyama_, May 19 2021