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 A302058 #11 Feb 16 2025 08:33:53
%S A302058 2,3,4,6,7,8,9,10,11,12,13,15,16,17,18,19,20,21,22,23,24,25,26,27,28,
%T A302058 29,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,
%U A302058 53,54,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82
%N A302058 Numbers that are not square pyramidal numbers.
%C A302058 Numbers not of the form 0^2 + 1^2 + 2^2 + ... + m^2 = m*(m + 1)*(2*m + 1)/6.
%H A302058 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SquarePyramidalNumber.html">Square Pyramidal Number</a>
%F A302058 a(n) = n+m if 6n>m(m-1)(2m+5) and a(n) = n+m-1 otherwise where m = floor((3n)^(1/3)). - _Chai Wah Wu_, Oct 01 2024
%t A302058 Module[{nn=6,m},m=(nn(nn+1)(2nn+1))/6 ;Complement[Range[m],Table[(n(n+1)(2n+1))/6,{n,nn}]]] (* _Harvey P. Dale_, Aug 22 2020 *)
%o A302058 (Python)
%o A302058 from sympy import integer_nthroot
%o A302058 def A302058(n): return n+(m:=integer_nthroot(3*n,3)[0])-(6*n<=m*(m-1)*(2*m+5)) # _Chai Wah Wu_, Oct 01 2024
%Y A302058 Complement of A000330.
%Y A302058 Cf. A000037, A014132, A145397, A253903.
%K A302058 nonn,easy
%O A302058 1,1
%A A302058 _Ilya Gutkovskiy_, Mar 31 2018