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 A383147 #18 Apr 25 2025 18:48:18
%S A383147 0,0,0,0,0,3,0,0,0,0,0,3,0,0,5,0,0,12,0,5,0,0,0,3,0,0,0,7,0,23,0,0,0,
%T A383147 0,7,12,0,0,0,5,0,31,0,0,29,0,0,3,0,0,0,0,0,39,0,7,0,0,0,23,0,0,9,0,0,
%U A383147 47,0,0,0,7,0,12,0,0,30,0,11,42,0,5,0,0,0,31,0,0,0,11,0,77,13,0,0,0,0
%N A383147 Sum of odd divisors m of n such that there is a divisor d of n with d < m < 2*d.
%F A383147 a(n) = A000593(n) - A379379(n).
%e A383147 For n = 18 there are two odd divisors m of 18 such that there is a divisor d of 18 with d < m < 2*d. Those odd divisors are 3 and 9 as shown below:
%e A383147 d < m < 2*d
%e A383147 --------------------
%e A383147 1 2
%e A383147 2 3 4
%e A383147 3 6
%e A383147 6 9 12
%e A383147 9 18
%e A383147 18 36
%e A383147 .
%e A383147 The sum of both divisors is 3 + 9 = 12, so a(18) = 12.
%t A383147 a[n_] := Module[{d = Partition[Divisors[n], 2, 1]}, Total[Select[d, OddQ[#[[2]]] && #[[2]] < 2*#[[1]] &][[;; , 2]]]]; Array[a, 100] (* _Amiram Eldar_, Apr 18 2025 *)
%Y A383147 Row sums of A383209.
%Y A383147 Cf. A000593, A237270, A237271, A237593, A239657, A379379.
%K A383147 nonn
%O A383147 1,6
%A A383147 _Omar E. Pol_, Apr 17 2025