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.

A349616 Dirichlet convolution of A000027 (the identity function) with the Dirichlet inverse of the inverse permutation of EKG-permutation.

Original entry on oeis.org

1, 0, -2, 1, -5, 6, -7, -2, 13, 11, -9, -6, -15, 15, 49, 0, -16, -42, -18, -15, 69, 21, -20, 24, 51, 29, -48, -21, -28, -168, -30, -1, 97, 34, 150, 65, -30, 38, 141, 48, -33, -236, -38, -32, -317, 44, -42, -40, 97, -163, 163, -36, -47, 248, 192, 75, 183, 58, -48, 294, -54, 62, -443, 1, 301, -338, -61, -50, 211
Offset: 1

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Author

Antti Karttunen, Nov 23 2021

Keywords

Crossrefs

Cf. A000027, A064413, A064664, A323411, A349617 (Dirichlet inverse).
Cf. also A349613, A349614.

Programs

  • PARI
    up_to = 32768;
    v064413 = readvec("b064413_upto65539_terms_only.txt"); \\ Data prepared with Chai Wah Wu's Dec 08 2014 Python-program given in A064413.
    A064413(n) = v064413[n];
    \\ Then its inverse A064664 was prepared:
    m064664 = Map();
    for(n=1,65539,mapput(m064664,A064413(n),n));
    A064664(n) = mapget(m064664,n);
    DirInverseCorrect(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = (-u[1]*sumdiv(n, d, if(dA064664(n)));
    A323411(n) = v323411[n];
    A349616(n) = sumdiv(n,d,d*A323411(n/d));

Formula

a(n) = Sum_{d|n} d * A323411(n/d).