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 A339363 #17 Apr 26 2021 14:05:57
%S A339363 0,1,1,2,3,4,4,4,6,7,8,9,9,9,9,12,13,14,15,16,16,16,16,16,20,21,22,23,
%T A339363 24,25,25,25,25,25,25,30,31,32,33,34,35,36,36,36,36,36,36,36,42,43,44,
%U A339363 45,46,47,48,49,49,49,49,49,49,49,49,56,57,58,59,60,61,62,63,64,64,64
%N A339363 a(n) = Sum_{k=1..floor(sqrt(n))} floor(sqrt(n-k)).
%C A339363 Contains all nonnegative integers not in A189151.
%t A339363 Table[Sum[Floor[Sqrt[n - k]], {k, Floor[Sqrt[n]]}], {n, 80}]
%o A339363 (PARI) a(n) = sum(k=1, sqrtint(n), sqrtint(n-k)); \\ _Michel Marcus_, Apr 24 2021
%o A339363 (Python)
%o A339363 from math import isqrt
%o A339363 def a(n): return sum(isqrt(n-k) for k in range(1, isqrt(n)+1))
%o A339363 print([a(n) for n in range(1, 75)]) # _Michael S. Branicky_, Apr 24 2021
%Y A339363 Cf. A189151.
%K A339363 nonn
%O A339363 1,4
%A A339363 _Wesley Ivan Hurt_, Apr 24 2021