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 A067436 #14 Mar 30 2024 03:00:21
%S A067436 0,0,2,2,8,6,16,16,24,26,44,34,56,62,72,72,102,94,128,122,140,154,196,
%T A067436 170,206,224,250,248,302,276,334,334,368,394,436,396,466,496,538,516,
%U A067436 594,568,650,656,678,716,806,748,828,840,898,908,1010,984,1058,1040
%N A067436 a(n) = sum of all the remainders when n-th even number is divided by even numbers < 2n.
%F A067436 a(n) = 2*A004125(n).
%F A067436 a(n) = (2 - Pi^2/6) * n^2 + O(n*log(n)). - _Amiram Eldar_, Mar 30 2024
%e A067436 a(5) = 8. The remainder when 10 is divided by 4,6,8, respectively is 2,4,2 and their sum = 8.
%t A067436 Accumulate[Table[4*n - 2*DivisorSigma[1, n] - 2, {n, 1, 100}]] (* _Amiram Eldar_, Mar 30 2024 *)
%o A067436 (Python)
%o A067436 from math import isqrt
%o A067436 def A067436(n): return (n**2<<1)+(s:=isqrt(n))**2*(s+1)-sum((q:=n//k)*((k<<1)+q+1) for k in range(1,s+1)) # _Chai Wah Wu_, Oct 22 2023
%Y A067436 Cf. A013661, A004125, A067435.
%K A067436 easy,nonn
%O A067436 1,3
%A A067436 _Amarnath Murthy_, Jan 29 2002
%E A067436 Corrected and extended by several contributors.