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 1-10 of 13 results. Next

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).

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)).

A348495 a(n) = gcd(A018804(n), A347130(n)), where A347130 is the Dirichlet convolution of the identity function with the arithmetic derivative of n (A003415), and A018804 is Pillai's arithmetical function.

Original entry on oeis.org

1, 1, 1, 2, 1, 5, 1, 4, 3, 1, 1, 8, 1, 3, 1, 16, 1, 63, 1, 72, 5, 1, 1, 4, 5, 15, 27, 8, 1, 1, 1, 16, 7, 1, 3, 6, 1, 3, 1, 4, 1, 1, 1, 24, 9, 5, 1, 80, 7, 15, 5, 8, 1, 81, 1, 4, 1, 1, 1, 24, 1, 3, 3, 32, 9, 1, 1, 24, 1, 1, 1, 12, 1, 3, 5, 8, 3, 1, 1, 16, 27, 1, 1, 8, 11, 15, 1, 140, 1, 9, 5, 72, 1, 1, 3, 16, 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/#]) &]], {n, 97}] (* 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]));
    A018804(n) = sumdiv(n, d, n*eulerphi(d)/d); \\ From A018804
    A347130(n) = sumdiv(n,d,d*A003415(n/d));
    A348495(n) = gcd(A018804(n), A347130(n));

Formula

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

A348498 a(n) = gcd(A003415(n), A347130(n)) / A003557(n), where A003415 is the arithmetic derivative and A347130 is its Dirichlet convolution with the identity function.

Original entry on oeis.org

0, 1, 1, 1, 1, 5, 1, 3, 1, 7, 1, 8, 1, 9, 8, 2, 1, 7, 1, 12, 10, 13, 1, 11, 1, 15, 3, 16, 1, 31, 1, 5, 14, 19, 12, 5, 1, 21, 16, 17, 1, 41, 1, 24, 13, 25, 1, 14, 1, 9, 20, 28, 1, 9, 16, 23, 22, 31, 1, 46, 1, 33, 17, 3, 18, 61, 1, 36, 26, 59, 1, 13, 1, 39, 11, 40, 18, 71, 1, 22, 2, 43, 1, 62, 22, 45, 32, 35, 1, 41
Offset: 1

Views

Author

Antti Karttunen, Oct 23 2021

Keywords

Crossrefs

Programs

  • Mathematica
    f[n_] := If[n < 2, 0, n Total[#2/#1 & @@@ FactorInteger[n]]]; Table[GCD[f[n], DivisorSum[n, # f[n/#] &]]*Apply[Times, FactorInteger[n][[All, 1]]]/n, {n, 90}] (* Michael De Vlieger, Oct 25 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]));
    A347130(n) = sumdiv(n,d,d*A003415(n/d));
    A348498(n) = (gcd(A003415(n), A347130(n))/A003557(n));

Formula

a(n) = A348497(n) / A003557(n).
a(n) = gcd(A342001(n), A347129(n)).

A348497 a(n) = gcd(A003415(n), A347130(n)), where A003415 is the arithmetic derivative and A347130 is its Dirichlet convolution with the identity function.

Original entry on oeis.org

0, 1, 1, 2, 1, 5, 1, 12, 3, 7, 1, 16, 1, 9, 8, 16, 1, 21, 1, 24, 10, 13, 1, 44, 5, 15, 27, 32, 1, 31, 1, 80, 14, 19, 12, 30, 1, 21, 16, 68, 1, 41, 1, 48, 39, 25, 1, 112, 7, 45, 20, 56, 1, 81, 16, 92, 22, 31, 1, 92, 1, 33, 51, 96, 18, 61, 1, 72, 26, 59, 1, 156, 1, 39, 55, 80, 18, 71, 1, 176, 54, 43, 1, 124, 22, 45
Offset: 1

Views

Author

Antti Karttunen, Oct 23 2021

Keywords

Crossrefs

Programs

  • Mathematica
    f[n_] := If[n < 2, 0, n Total[#2/#1 & @@@ FactorInteger[n]]]; Table[GCD[f[n], DivisorSum[n, # f[n/#] &]], {n, 86}] (* Michael De Vlieger, Oct 25 2021 *)
  • PARI
    A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
    A347130(n) = sumdiv(n,d,d*A003415(n/d));
    A348497(n) = gcd(A003415(n), A347130(n));

Formula

a(n) = gcd(A003415(n), A347130(n)).
a(n) = A003557(n) * A348498(n).

A347131 a(n) = Sum_{d|n} phi(n/d) * A003415(d), where A003415 is the arithmetic derivative and phi is Euler totient function.

Original entry on oeis.org

0, 1, 1, 5, 1, 8, 1, 18, 8, 12, 1, 33, 1, 16, 14, 56, 1, 45, 1, 53, 18, 24, 1, 110, 14, 28, 45, 73, 1, 87, 1, 160, 26, 36, 22, 169, 1, 40, 30, 182, 1, 119, 1, 113, 93, 48, 1, 328, 20, 107, 38, 133, 1, 216, 30, 254, 42, 60, 1, 337, 1, 64, 125, 432, 34, 183, 1, 173, 50, 183, 1, 538, 1, 76, 135, 193, 34, 215, 1, 552, 216
Offset: 1

Views

Author

Antti Karttunen, Aug 23 2021

Keywords

Comments

Dirichlet convolution of A000010 with A003415.

Crossrefs

Möbius transform of A347130.

Programs

  • Mathematica
    f[p_, e_] := e/p; d[1] = 0; d[n_] := n * Plus @@ f @@@ FactorInteger[n]; a[n_] := DivisorSum[n, d[#] * EulerPhi[n/#] &]; Array[a, 100] (* Amiram Eldar, Sep 03 2021 *)
  • PARI
    A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
    A347131(n) = sumdiv(n,d,A003415(n/d)*eulerphi(d));
    
  • PARI
    A347131(n) = sum(k=1,n,A003415(gcd(n,k))); \\ (Slow) - Antti Karttunen, Sep 02 2021

Formula

a(n) = Sum_{d|n} A000010(n/d) * A003415(d).
a(n) = Sum_{d|n} A008683(n/d) * A347130(d).
a(n) = Sum_{k=1..n} A003415(gcd(n,k)). - Antti Karttunen, Sep 02 2021

A348980 a(n) = Sum_{d|n} d * A322582(n/d), where A322582(n) = n - A003958(n), and A003958 is fully multiplicative with a(p) = (p-1).

Original entry on oeis.org

0, 1, 1, 5, 1, 9, 1, 17, 8, 13, 1, 37, 1, 17, 15, 49, 1, 51, 1, 57, 19, 25, 1, 117, 14, 29, 43, 77, 1, 105, 1, 129, 27, 37, 23, 191, 1, 41, 31, 185, 1, 141, 1, 117, 99, 49, 1, 325, 20, 117, 39, 137, 1, 237, 31, 253, 43, 61, 1, 405, 1, 65, 131, 321, 35, 213, 1, 177, 51, 209, 1, 579, 1, 77, 145, 197, 35, 249, 1, 521
Offset: 1

Views

Author

Antti Karttunen, Nov 08 2021

Keywords

Comments

Dirichlet convolution of A322582 with the identity function, A000027.

Crossrefs

Cf. A000027, A003958, A038040, A322582, A348981 (Möbius transform), A348982, A348983, A349130.
Cf. also A347130, A349140.

Programs

  • Mathematica
    f[p_, e_] := (p - 1)^e; s[1] = 1; s[n_] := Times @@ f @@@ FactorInteger[n]; a[n_] := DivisorSum[n, #*(n/# - s[n/#]) &]; Array[a, 100] (* Amiram Eldar, Nov 08 2021 *)
  • PARI
    A003958(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1]--); factorback(f); };
    A322582(n) = (n-A003958(n));
    A348980(n) = sumdiv(n,d,d*A322582(n/d));

Formula

a(n) = Sum_{d|n} d * A322582(n/d).
For all n >= 1, a(n) <= A347130(n) <= A349140(n).
a(n) = A038040(n) - A349130(n). - Antti Karttunen, Nov 14 2021

A349140 a(n) = Sum_{d|n} d * A348507(n/d), where A348507(n) = A003959(n) - n, where A003959 is fully multiplicative with a(p) = (p+1).

Original entry on oeis.org

0, 1, 1, 7, 1, 11, 1, 33, 10, 15, 1, 61, 1, 19, 17, 131, 1, 77, 1, 89, 21, 27, 1, 263, 16, 31, 67, 117, 1, 145, 1, 473, 29, 39, 25, 379, 1, 43, 33, 395, 1, 189, 1, 173, 137, 51, 1, 997, 22, 155, 41, 201, 1, 443, 33, 527, 45, 63, 1, 743, 1, 67, 177, 1611, 37, 277, 1, 257, 53, 265, 1, 1541, 1, 79, 187, 285, 37, 321
Offset: 1

Views

Author

Antti Karttunen, Nov 08 2021

Keywords

Comments

Dirichlet convolution of A348507 with the identity function, A000027.
Dirichlet convolution of sigma with A348971.

Crossrefs

Cf. also A347130, A348980.

Programs

  • Mathematica
    f[p_, e_] := (p + 1)^e; s[1] = 0; s[n_] := Times @@ f @@@ FactorInteger[n] - n; a[n_] := DivisorSum[n, #*s[n/#] &]; Array[a, 100] (* Amiram Eldar, Nov 08 2021 *)
  • PARI
    A003959(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1]++); factorback(f); };
    A348507(n) = (A003959(n) - n);
    A349140(n) = sumdiv(n,d,d*A348507(n/d));

Formula

a(n) = Sum_{d|n} d * A348507(n/d).
a(n) = Sum_{d|n} A000203(d) * A348971(n/d).
a(n) = Sum_{d|n} A349141(d).
For all n >= 1, a(n) >= A347130(n) >= A348980(n).
a(n) = A349170(n) - A038040(n). - Antti Karttunen, Nov 15 2021

A347126 a(n) = A347129(A276086(n)).

Original entry on oeis.org

0, 1, 1, 10, 3, 21, 1, 14, 16, 124, 39, 246, 3, 27, 33, 222, 72, 423, 6, 44, 56, 344, 114, 636, 10, 65, 85, 490, 165, 885, 1, 18, 20, 164, 51, 330, 24, 236, 284, 1976, 636, 3804, 57, 438, 552, 3468, 1143, 6462, 104, 696, 904, 5296, 1776, 9624, 165, 1010, 1340, 7460, 2535, 13290, 3, 33, 39, 282, 90, 549, 51, 414, 516
Offset: 0

Views

Author

Antti Karttunen, Aug 25 2021

Keywords

Crossrefs

Programs

Formula

a(n) = A347129(A276086(n)).

A359425 Dirichlet convolution of the arithmetic derivative with the primorial base exp-function.

Original entry on oeis.org

0, 2, 2, 11, 2, 19, 2, 45, 18, 35, 2, 85, 2, 31, 40, 151, 2, 125, 2, 195, 36, 119, 2, 313, 38, 83, 120, 215, 2, 418, 2, 649, 124, 491, 52, 628, 2, 295, 88, 1057, 2, 1046, 2, 1629, 414, 2303, 2, 1777, 38, 1541, 496, 2241, 2, 4424, 140, 6421, 300, 11315, 2, 2048, 2, 83, 1002, 2013, 104, 1864, 2, 2073
Offset: 1

Views

Author

Antti Karttunen, Jan 02 2023

Keywords

Crossrefs

Programs

  • PARI
    A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
    A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
    A359425(n) = sumdiv(n,d,A003415(n/d)*A276086(d));

Formula

a(n) = Sum_{d|n} A003415(n/d) * A276086(d).
a(n) = Sum_{d|n} A347130(n/d) * A383286(d). - Antti Karttunen, May 14 2025
Showing 1-10 of 13 results. Next