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 1-9 of 9 results.

A347396 a(n) = A347395(A276086(n)), where A347395 is Dirichlet convolution of Liouville's lambda with A342001.

Original entry on oeis.org

0, 1, 1, 3, 1, 2, 1, 5, 6, 14, 5, 9, 1, 2, 3, 5, 2, 3, 2, 6, 8, 16, 6, 10, 2, 3, 5, 7, 3, 4, 1, 7, 8, 20, 7, 13, 10, 34, 44, 92, 34, 58, 7, 13, 20, 32, 13, 19, 16, 40, 56, 104, 40, 64, 13, 19, 32, 44, 19, 25, 1, 2, 3, 5, 2, 3, 5, 9, 14, 22, 9, 13, 2, 3, 5, 7, 3, 4, 6, 10, 16, 24, 10, 14, 3, 4, 7, 9, 4, 5, 2, 8, 10, 22
Offset: 0

Views

Author

Antti Karttunen, Sep 02 2021

Keywords

Comments

The scatter plot looks quite peculiar. - Antti Karttunen, Sep 20 2021

Crossrefs

Programs

A366803 Dirichlet convolution of Liouville's lambda with A342001 applied to Doudna sequence: a(n) = A347395(A005940(1+n)).

Original entry on oeis.org

0, 1, 1, 1, 1, 3, 1, 2, 1, 5, 6, 3, 1, 2, 2, 2, 1, 7, 8, 5, 10, 14, 5, 5, 1, 2, 3, 2, 2, 4, 2, 3, 1, 11, 12, 7, 14, 20, 7, 9, 16, 34, 44, 14, 7, 9, 10, 5, 1, 2, 3, 2, 5, 5, 2, 3, 2, 6, 8, 4, 2, 3, 3, 3, 1, 13, 14, 11, 16, 32, 11, 13, 18, 54, 68, 20, 11, 13, 14, 9, 22, 76, 92, 34, 124, 92, 34, 22, 11, 13, 20, 9, 16
Offset: 0

Views

Author

Antti Karttunen, Oct 26 2023

Keywords

Crossrefs

Cf. A003415, A005940, A008836, A342001, A347395, A366805 (rgs-transform).
Cf. also A347396, A366795, A366801.

Programs

A342001 Arithmetic derivative without its inherited divisor; the arithmetic derivative of n divided by A003557(n), which is a common divisor of both n and A003415(n).

Original entry on oeis.org

0, 1, 1, 2, 1, 5, 1, 3, 2, 7, 1, 8, 1, 9, 8, 4, 1, 7, 1, 12, 10, 13, 1, 11, 2, 15, 3, 16, 1, 31, 1, 5, 14, 19, 12, 10, 1, 21, 16, 17, 1, 41, 1, 24, 13, 25, 1, 14, 2, 9, 20, 28, 1, 9, 16, 23, 22, 31, 1, 46, 1, 33, 17, 6, 18, 61, 1, 36, 26, 59, 1, 13, 1, 39, 11, 40, 18, 71, 1, 22, 4, 43, 1, 62, 22, 45, 32, 35, 1, 41, 20
Offset: 1

Views

Author

Antti Karttunen, Feb 28 2021

Keywords

Comments

See also the scatter plot of A342002 that seems to reveal some interesting internal structure in this sequence, not fully explained by the regularity of primorial base expansion used in the latter sequence. - Antti Karttunen, May 09 2022

Crossrefs

Cf. A342002 [= a(A276086(n))], A342463 [= a(A342456(n))], A351945 [= a(A181819(n))], A353571 [= a(A003961(n))].
Cf. A346485 (Möbius transform), A347395 (convolution with Liouville's lambda), A347961 (with itself), and A347234, A347235, A347954, A347959, A347963, A349396, A349612 (for convolutions with other sequences).
Cf. A007947.

Programs

  • Mathematica
    Array[#1/#2 & @@ {If[# < 2, 0, # Total[#2/#1 & @@@ FactorInteger[#]]] &@ Abs[#], #/Times @@ FactorInteger[#][[All, 1]]} &, 91] (* Michael De Vlieger, Mar 11 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]));
    A342001(n) = (A003415(n) / A003557(n));
    
  • Python
    from math import prod
    from sympy import factorint
    def A342001(n):
        q = prod(f:=factorint(n))
        return sum(q*e//p for p, e in f.items()) # Chai Wah Wu, Nov 04 2022

Formula

a(n) = A003415(n) / A003557(n).
For all n >= 0, a(A276086(n)) = A342002(n).
a(n) = A342414(n) * A342416(n) = A342459(n) * A342919(n). - Antti Karttunen, Apr 30 2022
Dirichlet g.f.: Dirichlet g.f. of A007947 * Sum_{p prime} p^s/((p^s-1)*(p^s+p-1)) = zeta(s) * Product_{p prime} (1+p^(1-s)-p^(-s)) * Sum_{p prime} p^s/((p^s-1)*(p^s+p-1)). - Sebastian Karlsson, May 05 2022
Sum_{k=1..n} a(k) ~ c * A065464 * Pi^2 * n^2 / 12, where c = Sum_{j>=2} (1/2 + (-1)^j * (Fibonacci(j) - 1/2))*PrimeZetaP(j) = 0.4526952873143153104685540856936425315834753528741817723313791528384... - Vaclav Kotesovec, May 09 2022

A347234 Dirichlet convolution of A126760 with A342001.

Original entry on oeis.org

0, 1, 1, 3, 1, 7, 1, 6, 3, 10, 1, 17, 1, 13, 11, 10, 1, 16, 1, 26, 14, 18, 1, 31, 4, 21, 6, 35, 1, 61, 1, 15, 19, 26, 17, 36, 1, 29, 22, 49, 1, 82, 1, 50, 28, 34, 1, 49, 5, 36, 27, 59, 1, 28, 22, 67, 30, 42, 1, 139, 1, 45, 37, 21, 25, 117, 1, 74, 35, 127, 1, 63, 1, 53, 40, 83, 25, 138, 1, 79, 10, 58, 1, 190, 30, 61
Offset: 1

Views

Author

Antti Karttunen, Aug 26 2021

Keywords

Crossrefs

Programs

Formula

a(n) = Sum_{d|n} A126760(d) * A342001(n/d).

A346485 Möbius transform of A342001, where A342001(n) = A003415(n)/A003557(n).

Original entry on oeis.org

0, 1, 1, 1, 1, 3, 1, 1, 1, 5, 1, 2, 1, 7, 6, 1, 1, 1, 1, 4, 8, 11, 1, 2, 1, 13, 1, 6, 1, 14, 1, 1, 12, 17, 10, 0, 1, 19, 14, 4, 1, 20, 1, 10, 4, 23, 1, 2, 1, 1, 18, 12, 1, 1, 14, 6, 20, 29, 1, 8, 1, 31, 6, 1, 16, 32, 1, 16, 24, 34, 1, 0, 1, 37, 2, 18, 16, 38, 1, 4, 1, 41, 1, 12, 20, 43, 30, 10, 1, 4, 18, 22, 32, 47
Offset: 1

Views

Author

Antti Karttunen, Aug 26 2021

Keywords

Comments

Conjecture 1: After the initial zero, the positions of other zeros is given by A036785.
Conjecture 2: No negative terms. Checked up to n = 2^24.

Crossrefs

Programs

Formula

a(n) = Sum_{d|n} A008683(n/d) * A342001(d).
Dirichlet g.f.: Product_{p prime} (1+p^(1-s)-p^(-s)) * Sum_{p prime} p^s/((p^s-1)*(p^s+p-1)). - Sebastian Karlsson, May 08 2022
Sum_{k=1..n} a(k) ~ c * A065464 * n^2 / 2, where c = Sum_{j>=2} (1/2 + (-1)^j * (Fibonacci(j) - 1/2))*PrimeZetaP(j) = 0.4526952873143153104685540856936425315834753528741817723313791528384... - Vaclav Kotesovec, Mar 04 2023

A347235 Dirichlet convolution of Euler phi with A342001, where A342001(n) = A003415(n) / A003557(n).

Original entry on oeis.org

0, 1, 1, 3, 1, 8, 1, 7, 4, 12, 1, 21, 1, 16, 14, 15, 1, 27, 1, 33, 18, 24, 1, 47, 6, 28, 13, 45, 1, 87, 1, 31, 26, 36, 22, 69, 1, 40, 30, 75, 1, 119, 1, 69, 51, 48, 1, 99, 8, 63, 38, 81, 1, 84, 30, 103, 42, 60, 1, 219, 1, 64, 67, 63, 34, 183, 1, 105, 50, 183, 1, 153, 1, 76, 75, 117, 34, 215, 1, 159, 40, 84, 1, 303, 42
Offset: 1

Views

Author

Antti Karttunen, Aug 26 2021

Keywords

Crossrefs

Programs

Formula

a(n) = Sum_{d|n} A000010(n/d) * A342001(d).
a(n) = Sum_{k=1..n} A342001(gcd(n,k)). - Antti Karttunen, Sep 02 2021

A369069 Dirichlet convolution of Liouville's lambda (A008836) with A083345, where A083345(n) = n' / gcd(n,n'), and n' stands for the arithmetic derivative of n, A003415.

Original entry on oeis.org

0, 1, 1, 0, 1, 3, 1, 3, 1, 5, 1, 0, 1, 7, 6, -1, 1, 2, 1, 0, 8, 11, 1, 8, 1, 13, 0, 0, 1, 14, 1, 6, 12, 17, 10, 0, 1, 19, 14, 14, 1, 20, 1, 0, 5, 23, 1, -3, 1, 2, 18, 0, 1, 0, 14, 20, 20, 29, 1, 0, 1, 31, 7, -3, 16, 32, 1, 0, 24, 34, 1, 5, 1, 37, 3, 0, 16, 38, 1, -5, 4, 41, 1, 0, 20, 43, 30, 32, 1, 9, 18, 0, 32, 47
Offset: 1

Views

Author

Antti Karttunen, Jan 16 2024

Keywords

Comments

In contrast to A347395, this sequence has also nonpositive values after the initial term. It seems that A342090 gives most of the positions of nonpositive terms here, apart from k = 0, 729, 1458, 3645, 5103, 5832, 7290, ..., etc.

Crossrefs

Programs

  • PARI
    A008836(n) = ((-1)^bigomega(n));
    A083345(n) = { my(f=factor(n)); numerator(vecsum(vector(#f~, i, f[i, 2]/f[i, 1]))); };
    A369069(n) = sumdiv(n,d,A008836(n/d)*A083345(d));

Formula

a(n) = Sum_{d|n} A008836(n/d) * A083345(d).

A349396 Dirichlet convolution of A342001 ({arithmetic derivative of n}/A003557(n)) with A055615 (Dirichlet inverse of n).

Original entry on oeis.org

0, 1, 1, 0, 1, 0, 1, -1, -1, 0, 1, -2, 1, 0, 0, -2, 1, -6, 1, -2, 0, 0, 1, -2, -3, 0, -3, -2, 1, 0, 1, -3, 0, 0, 0, 2, 1, 0, 0, -2, 1, 0, 1, -2, -6, 0, 1, -2, -5, -20, 0, -2, 1, -6, 0, -2, 0, 0, 1, 0, 1, 0, -6, -4, 0, 0, 1, -2, 0, 0, 1, 8, 1, 0, -20, -2, 0, 0, 1, -2, -5, 0, 1, 0, 0, 0, 0, -2, 1, 0, 0, -2, 0, 0, 0
Offset: 1

Views

Author

Antti Karttunen, Nov 18 2021

Keywords

Comments

Dirichlet convolution of this sequence with A000010 (Euler phi) is A346485.

Crossrefs

Cf. A346485, A347234, A347235, A347395, A347954, A347959, A347961, A347963 for Dirichlet convolutions of A342001 with other sequences.
Cf. also A349394.

Programs

Formula

a(n) = Sum_{d|n} A055615(d) * A342001(n/d).

A366805 Lexicographically earliest infinite sequence such that a(i) = a(j) => A366803(i) = A366803(j) for all i, j >= 0.

Original entry on oeis.org

1, 2, 2, 2, 2, 3, 2, 4, 2, 5, 6, 3, 2, 4, 4, 4, 2, 7, 8, 5, 9, 10, 5, 5, 2, 4, 3, 4, 4, 11, 4, 3, 2, 12, 13, 7, 10, 14, 7, 15, 16, 17, 18, 10, 7, 15, 9, 5, 2, 4, 3, 4, 5, 5, 4, 3, 4, 6, 8, 11, 4, 3, 3, 3, 2, 19, 10, 12, 16, 20, 12, 19, 21, 22, 23, 14, 12, 19, 10, 15, 24, 25, 26, 17, 27, 26, 17, 24, 12, 19, 14, 15
Offset: 0

Views

Author

Antti Karttunen, Oct 26 2023

Keywords

Comments

Restricted growth sequence transform of A366803.
The scatter plot has quite interesting structure.

Crossrefs

Programs

  • PARI
    \\ Needs also program from A366803:
    up_to = 65537;
    rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };
    v366805 = rgs_transform(vector(1+up_to,n,A366803(n-1)));
    A366805(n) = v366805[1+n];
Showing 1-9 of 9 results.