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 1-4 of 4 results.

A347129 a(n) = A347130(n) / A003557(n), where A347130 is the Dirichlet convolution of the identity function with the arithmetic derivative of n.

Original entry on oeis.org

0, 1, 1, 3, 1, 10, 1, 6, 3, 14, 1, 24, 1, 18, 16, 10, 1, 21, 1, 36, 20, 26, 1, 44, 3, 30, 6, 48, 1, 124, 1, 15, 28, 38, 24, 45, 1, 42, 32, 68, 1, 164, 1, 72, 39, 50, 1, 70, 3, 27, 40, 84, 1, 36, 32, 92, 44, 62, 1, 276, 1, 66, 51, 21, 36, 244, 1, 108, 52, 236, 1, 78, 1, 78, 33, 120, 36, 284, 1, 110, 10, 86, 1, 372, 44
Offset: 1

Views

Author

Antti Karttunen, Aug 23 2021

Keywords

Crossrefs

Programs

Formula

a(n) = A347130(n) / A003557(n).

A348494 a(n) = A348492(n) / A003557(n), where A348492 is the GCD of the arithmetic derivative (A003415) and Pillai's arithmetical function (A018804).

Original entry on oeis.org

1, 1, 1, 2, 1, 5, 1, 1, 1, 1, 1, 4, 1, 3, 1, 2, 1, 7, 1, 12, 5, 1, 1, 1, 1, 15, 3, 4, 1, 1, 1, 1, 7, 1, 3, 2, 1, 3, 1, 1, 1, 1, 1, 12, 1, 5, 1, 2, 1, 3, 5, 4, 1, 9, 1, 1, 1, 1, 1, 2, 1, 3, 1, 2, 9, 1, 1, 12, 1, 1, 1, 1, 1, 3, 1, 4, 3, 1, 1, 2, 1, 1, 1, 2, 11, 15, 1, 35, 1, 1, 5, 12, 1, 1, 3, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1
Offset: 1

Views

Author

Antti Karttunen, Oct 21 2021

Keywords

Crossrefs

Programs

  • Mathematica
    Array[GCD[Total@ GCD[#1, Range[#1]], #1 Total[#2/#1 & @@@ #2]]/Apply[Times, Map[#1^(#2 - 1) & @@ # &, #2]] & @@ {#, FactorInteger[#]} &, 105] (* Michael De Vlieger, Oct 21 2021 *)
  • PARI
    A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
    A003557(n) = (n/factorback(factorint(n)[, 1]));
    A018804(n) = sumdiv(n, d, n*eulerphi(d)/d); \\ From A018804
    A348492(n) = gcd(A003415(n), A018804(n));
    A348494(n) = (A348492(n)/A003557(n));

Formula

a(n) = gcd(A342001(n), A347128(n)).
a(n) = A348492(n) / A003557(n), where A348492(n) = gcd(A003415(n), A018804(n)).

A348496 a(n) = gcd(A018804(n), A347130(n)) / A003557(n).

Original entry on oeis.org

1, 1, 1, 1, 1, 5, 1, 1, 1, 1, 1, 4, 1, 3, 1, 2, 1, 21, 1, 36, 5, 1, 1, 1, 1, 15, 3, 4, 1, 1, 1, 1, 7, 1, 3, 1, 1, 3, 1, 1, 1, 1, 1, 12, 3, 5, 1, 10, 1, 3, 5, 4, 1, 9, 1, 1, 1, 1, 1, 12, 1, 3, 1, 1, 9, 1, 1, 12, 1, 1, 1, 1, 1, 3, 1, 4, 3, 1, 1, 2, 1, 1, 1, 4, 11, 15, 1, 35, 1, 3, 5, 36, 1, 1, 3, 1, 1, 3, 3, 1, 1
Offset: 1

Views

Author

Antti Karttunen, Oct 21 2021

Keywords

Crossrefs

Programs

  • Mathematica
    Table[GCD[Total@ GCD[n, Range[n]], DivisorSum[n, #*(If[# < 2, 0, # Total[#2/#1 & @@@ FactorInteger[#]]] &[n/#]) &]]/Apply[Times, Map[#1^(#2 - 1) & @@ # &, FactorInteger[n]]], {n, 101}] (* Michael De Vlieger, Oct 21 2021 *)
  • PARI
    \\ Needs also code from A348495:
    A003557(n) = (n/factorback(factorint(n)[, 1]));
    A348496(n) = (A348495(n)/A003557(n));

Formula

a(n) = A348495(n) / A003557(n).
a(n) = gcd(A347128(n), A347129(n)).

A347127 a(n) = A327251(n) / A003557(n).

Original entry on oeis.org

1, 5, 7, 8, 11, 35, 15, 11, 11, 55, 23, 56, 27, 75, 77, 14, 35, 55, 39, 88, 105, 115, 47, 77, 17, 135, 15, 120, 59, 385, 63, 17, 161, 175, 165, 88, 75, 195, 189, 121, 83, 525, 87, 184, 121, 235, 95, 98, 23, 85, 245, 216, 107, 75, 253, 165, 273, 295, 119, 616, 123, 315, 165, 20, 297, 805, 135, 280, 329, 825, 143, 121
Offset: 1

Views

Author

Antti Karttunen, Aug 23 2021

Keywords

Crossrefs

Programs

  • Mathematica
    f[p_, e_] := (p + 1)*e + p; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Aug 24 2021 *)
  • PARI
    A347127(n) = { my(f=factor(n)); prod(i=1, #f~, ((f[i, 1]+1)*f[i, 2] + f[i, 1])); };
    
  • PARI
    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
    A003557(n) = (n/factorback(factorint(n)[, 1]));
    A327251(n) = sumdiv(n, d, A001615(n/d)*d);
    A347127(n) = (A327251(n) / A003557(n));

Formula

Multiplicative with a(p^e) = ((p+1)*e + p) for prime p.
a(n) = A327251(n) / A003557(n).
Showing 1-4 of 4 results.