cp's OEIS Frontend

A326050 a(n) = A082052(n) - n, where A082052 is the sum of divisors of n that are not of the form 4k+1.

%I A326050 #8 Jul 12 2024 12:08:38
%S A326050 -1,0,0,2,-5,5,0,6,-6,2,0,15,-13,9,3,14,-17,11,0,16,-11,13,0,35,-25,2,
%T A326050 3,27,-29,36,0,30,-19,2,7,45,-37,21,3,44,-41,32,0,39,-27,25,0,75,-42,
%U A326050 12,3,32,-53,56,11,63,-35,2,0,102,-61,33,10,62,-65,44,0,40,-43,68,0,113,-73,2,18,63,-59,76,0,100,-51,2,0,118,-85,45,3
%N A326050 a(n) = A082052(n) - n, where A082052 is the sum of divisors of n that are not of the form 4k+1.
%H A326050 Antti Karttunen, <a href="/A326050/b326050.txt">Table of n, a(n) for n = 1..20000</a>
%F A326050 a(n) = A082052(n) - n.
%F A326050 a(n) = A326049(n) - A033879(n).
%t A326050 Table[Total[Select[Divisors[n],Mod[#-1,4]!=0&]]-n,{n,90}] (* _Harvey P. Dale_, Jul 12 2024 *)
%o A326050 (PARI)
%o A326050 A082052(n) = sumdiv(n, d, if(1!=(d%4), d));
%o A326050 A326050(n) = (A082052(n)-n);
%Y A326050 Cf. A033879, A082052, A326048, A326049.
%K A326050 sign
%O A326050 1,4
%A A326050 _Antti Karttunen_, Jun 04 2019