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 A349490 #104 Dec 10 2021 01:58:27
%S A349490 1,10,153,3108,79225,2437006,87922513,3642188936,170423429841,
%T A349490 8891285549650,511800291063721,32222868466588460,2202868653419747209,
%U A349490 162509566498902542934,12868118600594014094625,1088626666242258867384848,97994054039441765759931169
%N A349490 Sum of the n-th powers of the first n odd numbers.
%F A349490 a(n) = Sum_{k=1..n} (2*k-1)^n.
%F A349490 a(n) ~ 2^n * n^n / (exp(1/2) - exp(-1/2)). - _Vaclav Kotesovec_, Dec 09 2021
%t A349490 Table[Sum[(2*k-1)^n, {k,1,n}], {n,1,20}] (* _Vaclav Kotesovec_, Dec 09 2021 *)
%o A349490 (PARI) a(n) = sum(k=1, n, (2*k-1)^n);
%Y A349490 Sum of the k-th powers of the first n odd numbers: A000290 (k=1), A000447 (k=2), A002593 (k=3), A002309 (k=4), A002594 (k=5), A259322 (k=6).
%Y A349490 Cf. A005408, A031971, A061787, A103438.
%K A349490 nonn
%O A349490 1,2
%A A349490 _Seiichi Manyama_, Dec 09 2021