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 A362059 #19 Apr 26 2023 07:56:11 %S A362059 0,1,1,3,3,5,5,8,8,10,10,14,14,16,16,20,20,23,23,27,27,29,29,35,35,37, %T A362059 37,41,41,45,45,50,50,52,52,58,58,60,60,66,66,70,70,74,74,76,76,84,84, %U A362059 87,87,91,91,95,95,101,101,103,103,111,111,113,113,119,119,123,123,127,127,131,131,140,140,142,142,146 %N A362059 Total number of even divisors of all positive integers <= n. %C A362059 Convolved with A002865 gives A066898. %F A362059 a(2n-1) = A006218(n-1), n >= 1. %F A362059 a(2n) = A006218(n), n >= 1. %t A362059 d[n_] := (e = IntegerExponent[n, 2]) * DivisorSigma[0, n/2^e]; Accumulate@ Array[d, 100] (* _Amiram Eldar_, Apr 07 2023 *) %o A362059 (Python) %o A362059 from math import isqrt %o A362059 def A362059(n): return -(q:=isqrt(m:=n>>1))**2+(sum(m//k for k in range(1, q+1))<<1) # _Chai Wah Wu_, Apr 26 2023 %Y A362059 Partial sums of A183063. %Y A362059 Cf. A000005, A002865, A006218, A066898, A060831, A271342. %K A362059 nonn,easy %O A362059 1,4 %A A362059 _Omar E. Pol_, Apr 06 2023