cp's OEIS Frontend

A326049 a(n) = n - A050449(n), where A050449 is the sum of divisors of the form 4k+1.

%I A326049 #10 Jun 04 2019 16:33:13
%S A326049 0,1,2,3,-1,5,6,7,-1,4,10,11,-1,13,9,15,-1,8,18,14,-1,21,22,23,-6,12,
%T A326049 17,27,-1,24,30,31,-1,16,29,26,-1,37,25,34,-1,20,42,43,-15,45,46,47,
%U A326049 -1,19,33,38,-1,44,49,55,-1,28,58,54,-1,61,32,63,-19,32,66,50,-1,64,70,62,-1,36,44,75,-1,64,78,74,-10,40
%N A326049 a(n) = n - A050449(n), where A050449 is the sum of divisors of the form 4k+1.
%H A326049 Antti Karttunen, <a href="/A326049/b326049.txt">Table of n, a(n) for n = 1..20000</a>
%F A326049 a(n) = n - A050449(n).
%F A326049 a(n) = A326050(n) + A033879(n).
%o A326049 (PARI)
%o A326049 A050449(n) = sumdiv(n, d, d*((d % 4) == 1)); \\ From A050449
%o A326049 A326049(n) = (n-A050449(n));
%Y A326049 Cf. A033879, A050449, A326047, A326048, A326050, A326052.
%K A326049 sign
%O A326049 1,3
%A A326049 _Antti Karttunen_, Jun 04 2019