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 A349489 #3 Nov 19 2021 20:44:45
%S A349489 1,3,9,17,32,50,71,95,131,171,215,263,328,398,473,553,638,728,842,962,
%T A349489 1088,1220,1358,1502,1677,1859,2048,2244,2447,2657,2874,3098,3362,
%U A349489 3634,3914,4202,4498,4802,5114,5434,5803,6181,6568,6964,7369,7783,8206,8638,9079,9529,10039
%N A349489 a(n) = Sum_{k=1..n} k * floor(sqrt(2*k-1)).
%t A349489 Table[Sum[k*Floor[Sqrt[2 k - 1]], {k, n}], {n, 80}]
%Y A349489 Cf. A103128, A337134.
%K A349489 nonn
%O A349489 1,2
%A A349489 _Wesley Ivan Hurt_, Nov 19 2021