cp's OEIS Frontend

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.

A347093 Sum of A322577 (convolution of Dedekind psi with Euler phi) and its Dirichlet inverse.

Original entry on oeis.org

2, 0, 0, 16, 0, 48, 0, 24, 36, 80, 0, 36, 0, 112, 120, 73, 0, 64, 0, 60, 168, 176, 0, 192, 100, 208, 96, 84, 0, 0, 0, 156, 264, 272, 280, 336, 0, 304, 312, 320, 0, 0, 0, 132, 160, 368, 0, 378, 196, 192, 408, 156, 0, 432, 440, 448, 456, 464, 0, 960, 0, 496, 224, 373, 520, 0, 0, 204, 552, 0, 0, 688, 0, 592, 288, 228, 616
Offset: 1

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Author

Antti Karttunen, Aug 18 2021

Keywords

Comments

No negative terms in range 1 .. 2^20.
Apparently, A030059 gives the positions of all zeros.

Crossrefs

Programs

  • PARI
    up_to = 16384;
    A001615(n) = if(1==n,n, my(f=factor(n)); prod(i=1, #f~, f[i, 1]^f[i, 2] + f[i, 1]^(f[i, 2]-1))); \\ After code in A001615
    A322577(n) = sumdiv(n,d,A001615(n/d)*eulerphi(d));
    DirInverseCorrect(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = (-u[1]*sumdiv(n, d, if(dA322577(n)));
    A347092(n) = v347092[n];
    A347093(n) = (A322577(n)+A347092(n));

Formula

a(n) = A322577(n) + A347092(n).
For n > 1, a(n) = -Sum_{d|n, 1A322577(d) * A347092(n/d).
For all n >= 1, a(A030059(n)) = 0, a(A030229(n)) = 2*A322577(A030229(n)).