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.

Showing 1-2 of 2 results.

A323411 Dirichlet inverse of A064664, the inverse permutation of EKG-sequence.

Original entry on oeis.org

1, -2, -5, 1, -10, 16, -14, -4, 19, 31, -20, -21, -28, 43, 89, 4, -33, -98, -37, -42, 125, 61, -43, 48, 76, 85, -87, -58, -57, -409, -61, -1, 179, 100, 255, 203, -67, 112, 251, 98, -74, -573, -81, -85, -559, 130, -89, -100, 146, -370, 296, -107, -100, 548, 347, 145, 332, 172, -107, 846, -115, 184, -783, 3, 506, -825, -128
Offset: 1

Views

Author

Antti Karttunen, Jan 13 2019

Keywords

Crossrefs

Programs

  • PARI
    up_to = 32768;
    v064413 = readvec("b064413_upto65539_terms_only.txt"); \\ From precomputed file.
    A064413(n) = v064413[n];
    \\ Then its inverse A064664 is prepared:
    m064664 = Map();
    for(n=1,65539,mapput(m064664,A064413(n),n));
    A064664(n) = mapget(m064664,n);
    DirInverse(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = -sumdiv(n, d, if(dA064664(n)));
    A323411(n) = v323411[n];

A318665 Denominators of the sequence whose Dirichlet convolution with itself yields A064664, the inverse permutation of EKG-sequence.

Original entry on oeis.org

1, 1, 2, 1, 1, 2, 1, 1, 8, 2, 1, 2, 1, 2, 1, 1, 2, 8, 2, 2, 1, 2, 2, 2, 2, 2, 16, 2, 2, 4, 2, 2, 2, 2, 2, 8, 2, 2, 2, 1, 1, 4, 2, 1, 8, 2, 2, 2, 2, 1, 4, 1, 1, 16, 2, 2, 4, 2, 2, 4, 2, 2, 8, 1, 1, 4, 1, 2, 4, 1, 1, 8, 1, 2, 4, 2, 1, 4, 2, 1, 128, 2, 1, 4, 2, 2, 4, 1, 2, 16, 2, 2, 4, 2, 1, 4, 1, 1, 2, 8, 2, 4, 2, 2, 4
Offset: 1

Views

Author

Antti Karttunen, Sep 01 2018

Keywords

Crossrefs

Cf. A064664, A304526, A304527, A318664 (numerators).

Programs

  • PARI
    v064413 = readvec("b064413_upto65539_terms_only.txt"); \\ From b-file of A064413 prepared previously.
    A064413(n) = v064413[n];
    m064664 = Map();
    for(n=1,65539,mapput(m064664,A064413(n),n));
    A064664(n) = mapget(m064664,n);
    up_to = (2^14);
    DirSqrt(v) = {my(n=#v, u=vector(n)); u[1]=1; for(n=2, n, u[n]=(v[n]/v[1] - sumdiv(n, d, if(d>1&&dA317937.
    v318664_65 = DirSqrt(vector(up_to, n, A064664(n)));
    A318664(n) = numerator(v318664_65[n]);
    A318665(n) = denominator(v318664_65[n]);

Formula

a(n) = denominator of f(n), where f(1) = 1, f(n) = (1/2) * (A064664(n) - Sum_{d|n, d>1, d 1.
Showing 1-2 of 2 results.