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 A378532 #8 Dec 01 2024 13:41:11 %S A378532 1,0,0,-2,0,-3,0,-2,-2,-3,0,-4,0,-3,-3,-2,0,-4,0,-4,-3,-3,0,-2,-2,-3, %T A378532 -2,-4,0,-6,0,-2,-3,-3,-3,-1,0,-3,-3,-2,0,-6,0,-4,-4,-3,0,-2,-2,-4,-3, %U A378532 -4,0,-2,-3,-2,-3,-3,0,0,0,-3,-4,-2,-3,-6,0,-4,-3,-6,0,0,0,-3,-4,-4,-3,-6,0,-2,-2,-3,0,0,-3,-3,-3,-2 %N A378532 Dirichlet convolution of A296075 and A378525. %C A378532 Inverse Möbius transform of A378534. %H A378532 Antti Karttunen, <a href="/A378532/b378532.txt">Table of n, a(n) for n = 1..65537</a> %F A378532 a(n) = Sum_{d|n} A296075(d)*A378525(n/d). %F A378532 a(n) = Sum_{d|n} A378534(d). %o A378532 (PARI) %o A378532 A033879(n) = ((2*n)-sigma(n)); %o A378532 A296075(n) = sumdiv(n,d,A033879(d)); %o A378532 A378542(n) = sumdiv(n,d,d*!(bigomega(n/d)%2)); %o A378532 memoA378525 = Map(); %o A378532 A378525(n) = if(1==n,1,my(v); if(mapisdefined(memoA378525,n,&v), v, v = -sumdiv(n,d,if(d<n,A378542(n/d)*A378525(d),0)); mapput(memoA378525,n,v); (v))); %o A378532 A378532(n) = sumdiv(n,d,A296075(d)*A378525(n/d)); %Y A378532 Cf. A033879, A296075, A378531 (Dirichlet inverse), A378534 (Möbius transform), A378525, A378542. %Y A378532 Cf. also A378218. %K A378532 sign %O A378532 1,4 %A A378532 _Antti Karttunen_, Dec 01 2024