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 1-3 of 3 results.

A378223 Inverse Möbius transform of A345182.

Original entry on oeis.org

1, 1, 2, 2, 2, 4, 2, 4, 4, 4, 2, 10, 2, 4, 6, 8, 2, 12, 2, 10, 6, 4, 2, 24, 4, 4, 8, 10, 2, 20, 2, 16, 6, 4, 6, 36, 2, 4, 6, 24, 2, 20, 2, 10, 16, 4, 2, 56, 4, 12, 6, 10, 2, 32, 6, 24, 6, 4, 2, 62, 2, 4, 16, 32, 6, 20, 2, 10, 6, 20, 2, 100, 2, 4, 16, 10, 6, 20, 2, 56, 16, 4, 2, 62, 6, 4, 6, 24, 2, 72, 6, 10, 6, 4, 6
Offset: 1

Views

Author

Antti Karttunen, Nov 25 2024

Keywords

Comments

Apparently the Dirichlet convolution of A002131 and A323910. - Antti Karttunen, Nov 30 2024

Crossrefs

Cf. A002131, A323910, A345182, A378224 (Dirichlet inverse).
Cf. also A067824.
Odd bisection is not equal to A278223.

Programs

  • PARI
    memoA345182 = Map();
    A345182(n) = if(n<=2, n%2, my(v); if(mapisdefined(memoA345182,n,&v), v, v = sumdiv(n,d,if(dA345182(d),0)); mapput(memoA345182,n,v); (v)));
    A378223(n) = sumdiv(n,d,A345182(d));
    
  • PARI
    up_to = 20000;
    A378223list(up_to_n) = { my(v=vector(up_to_n)); v[1] = 1; v[2] = 0; for(n=3,up_to_n,v[n] = 1+sumdiv(n,d,(dA378223list(up_to);
    A378223(n) = v378223[n];

Formula

a(n) = Sum_{d|n} A345182(d).
For n > 2, a(n) = 2*A345182(n).

A378225 Dirichlet inverse of A067824.

Original entry on oeis.org

1, -2, -2, 0, -2, 2, -2, 0, 0, 2, -2, 0, -2, 2, 2, 0, -2, 0, -2, 0, 2, 2, -2, 0, 0, 2, 0, 0, -2, -2, -2, 0, 2, 2, 2, 0, -2, 2, 2, 0, -2, -2, -2, 0, 0, 2, -2, 0, 0, 0, 2, 0, -2, 0, 2, 0, 2, 2, -2, 0, -2, 2, 0, 0, 2, -2, -2, 0, 2, -2, -2, 0, -2, 2, 0, 0, 2, -2, -2, 0, 0, 2, -2, 0, 2, 2, 2, 0, -2, 0, 2, 0, 2, 2, 2, 0, -2
Offset: 1

Views

Author

Antti Karttunen, Nov 25 2024

Keywords

Comments

Möbius transform of A153881.

Crossrefs

Cf. also A378224.

Programs

Formula

a(1) = 1, and for n > 1, a(n) = -Sum_{d|n, dA067824(n/d) * a(d).
a(n) = Sum_{d|n} A008683(n/d)*A153881(d).
Dirichlet g.f.: (2 - zeta(s)) / zeta(s). [See Dec 30 2018 formula in A067824]

A378534 Dirichlet convolution of A033879 and A378525.

Original entry on oeis.org

1, -1, -1, -2, -1, -2, -1, 0, -2, -2, -1, 1, -1, -2, -2, 0, -1, 1, -1, 1, -2, -2, -1, 2, -2, -2, 0, 1, -1, 2, -1, 0, -2, -2, -2, 4, -1, -2, -2, 2, -1, 2, -1, 1, 1, -2, -1, 0, -2, 1, -2, 1, -1, 2, -2, 2, -2, -2, -1, 6, -1, -2, 1, 0, -2, 2, -1, 1, -2, 2, -1, -1, -1, -2, 1, 1, -2, 2, -1, 0, 0, -2, -1, 6, -2, -2, -2, 2, -1, 6
Offset: 1

Views

Author

Antti Karttunen, Dec 01 2024

Keywords

Comments

Möbius transform of A378532.

Crossrefs

Cf. A008683, A033879, A323910, A378532 (inverse Möbius transform), A378533 (Dirichlet inverse), A378542.
Cf. also A378224.

Programs

Formula

a(n) = Sum_{d|n} A033879(d)*A378525(n/d).
a(n) = Sum_{d|n} A008683(d)*A378532(n/d).
Showing 1-3 of 3 results.