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 A378751 #10 Dec 09 2024 19:45:53
%S A378751 0,1,1,2,2,4,2,1,0,7,5,5,5,7,6,-10,8,1,8,10,4,16,9,-8,6,16,-23,6,14,
%T A378751 19,13,-59,15,25,9,-22,17,25,13,-5,20,13,20,25,-10,28,21,-79,-4,19,24,
%U A378751 21,24,-68,26,-29,22,43,29,10,28,40,-34,-238,24,46,32,40,23,28,35,-143,34,52,1,36,24,40,38,-98,-192
%N A378751 a(n) = A000203(n) - A048673(n).
%H A378751 Antti Karttunen, <a href="/A378751/b378751.txt">Table of n, a(n) for n = 1..20000</a>
%H A378751 <a href="/index/Pri#prime_indices">Index entries for sequences related to prime indices in the factorization of n</a>.
%H A378751 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>.
%F A378751 a(n) = n - A378747(n).
%F A378751 a(n) = (1/2) * (A377984(n)-1).
%o A378751 (PARI)
%o A378751 A048673(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); (factorback(f)+1)/2; };
%o A378751 A378751(n) = (sigma(n)-A048673(n));
%Y A378751 Cf. A000203, A048673, A377984, A378747.
%Y A378751 Cf. A337378 (positions of negative terms), A337379 (of terms >= 0).
%K A378751 sign
%O A378751 1,4
%A A378751 _Antti Karttunen_, Dec 09 2024