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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.

A349377 Dirichlet convolution of A006369 with the Dirichlet inverse of A006368, where A006368 is the "amusical permutation", and A006369 is its inverse permutation.

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%I A349377 #8 Nov 25 2021 17:32:44
%S A349377 1,0,0,-1,3,-5,4,2,-1,-11,7,7,7,-14,-7,-3,10,-2,11,16,-10,-25,14,-6,2,
%T A349377 -25,0,18,17,11,18,4,-17,-36,-10,20,21,-39,-17,-18,24,12,25,34,-7,-50,
%U A349377 28,2,8,-15,-24,34,31,3,-20,-16,-27,-61,35,30,35,-64,-8,-5,-20,23,39,50,-34,6,42,-44,42,-75,-15,52,-22,23
%N A349377 Dirichlet convolution of A006369 with the Dirichlet inverse of A006368, where A006368 is the "amusical permutation", and A006369 is its inverse permutation.
%C A349377 Obviously, convolving this sequence with A006368 gives its inverse A006369 from n >= 1 onward.
%H A349377 Antti Karttunen, <a href="/A349377/b349377.txt">Table of n, a(n) for n = 1..20000</a>
%F A349377 a(n) = Sum_{d|n} A006369(d) * A349351(n/d).
%F A349377 a(n) = A349378(n) - A349376(n).
%o A349377 (PARI)
%o A349377 A006368(n) = ((3*n)+(n%2))\(2+((n%2)*2));
%o A349377 A006369(n) = if(!(n%3),(2/3)*n,(1/3)*if(1==(n%3),((4*n)-1),((4*n)+1)));
%o A349377 memoA349351 = Map();
%o A349377 A349351(n) = if(1==n,1,my(v); if(mapisdefined(memoA349351,n,&v), v, v = -sumdiv(n,d,if(d<n,A006368(n/d)*A349351(d),0)); mapput(memoA349351,n,v); (v)));
%o A349377 A349377(n) = sumdiv(n,d,A006369(d)*A349351(n/d));
%Y A349377 Cf. A006368, A006369, A349351, A349376 (Dirichlet inverse), A349378 (sum with it).
%Y A349377 Cf. also pairs A349613, A349614 and A349397, A349398 for similar constructions.
%K A349377 sign
%O A349377 1,5
%A A349377 _Antti Karttunen_, Nov 17 2021