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 A382311 #5 Mar 22 2025 08:43:44 %S A382311 0,5,15,28,52,81,123,176,240,325,425,542,684,849,1037,1250,1498,1775, %T A382311 2083,2424,2806,3227,3687,4188,4732,5329,5973,6666,7410,8207,9065, %U A382311 9982,10958,11995,13095,14260,15500,16809,18189,19642,21170,22775,24465,26238,28094,30035 %N A382311 Antidiagonal sums of A382310. %F A382311 a(n) = (2*(6*n^2 - 30*n - 23)*floor(n-2*sqrt(n+1)) - (12*n - 6)*floor(n - 2*sqrt(n+1))^2 + 4*floor(n - 2*sqrt(n+1))^3 - 84 - 61*n + 45*n^2 - 2*n^3)/6. %F A382311 a(n) ~ n^3/3. %t A382311 a[n_]:=(2(6n^2-30n-23)Floor[n-2Sqrt[n+1]]-(12n-6)Floor[n-2Sqrt[n+1]]^2+4Floor[n-2Sqrt[n+1]]^3-84-61n+45n^2-2n^3)/6; Array[a,46,0] %Y A382311 Cf. A382310. %K A382311 nonn %O A382311 0,2 %A A382311 _Stefano Spezia_, Mar 21 2025