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 154 results. Next

A349136 Möbius transform of Kimberling's paraphrases, A003602.

Original entry on oeis.org

1, 0, 1, 0, 2, 0, 3, 0, 3, 0, 5, 0, 6, 0, 4, 0, 8, 0, 9, 0, 6, 0, 11, 0, 10, 0, 9, 0, 14, 0, 15, 0, 10, 0, 12, 0, 18, 0, 12, 0, 20, 0, 21, 0, 12, 0, 23, 0, 21, 0, 16, 0, 26, 0, 20, 0, 18, 0, 29, 0, 30, 0, 18, 0, 24, 0, 33, 0, 22, 0, 35, 0, 36, 0, 20, 0, 30, 0, 39, 0, 27, 0, 41, 0, 32, 0, 28, 0, 44, 0, 36, 0, 30, 0, 36
Offset: 1

Views

Author

Antti Karttunen, Nov 13 2021

Keywords

Crossrefs

Agrees with A055034 on odd arguments.
Cf. A000004, A072451 (even and odd bisection).
Cf. also A347233, A349127, A349137.

Programs

  • Maple
    with(numtheory): a:=proc(n) if n=1 then 1; elif n mod 2 = 0 then 0; else phi(n)/2; fi: end proc: seq(a(n), n=1..60); # Ridouane Oudra, Jul 13 2023
  • Mathematica
    k[n_] := (n/2^IntegerExponent[n, 2] + 1)/2; a[n_] := DivisorSum[n, MoebiusMu[#] * k[n/#] &]; Array[a, 100] (* Amiram Eldar, Nov 13 2021 *)
  • PARI
    A349136(n) = if(1==n,1, if(n%2, eulerphi(n)/2, 0));
    
  • PARI
    A003602(n) = (1+(n>>valuation(n,2)))/2;
    A349136(n) = sumdiv(n,d,moebius(d)*A003602(n/d));
    
  • Python
    from sympy import totient
    def A349136(n): return totient(n)+1>>1 if n&1 else 0 # Chai Wah Wu, Nov 24 2023

Formula

a(n) = Sum_{d|n} A008683(d) * A003602(n/d).
a(1) = 1, a(n) = A000010(n)/2 for odd n > 1, a(n) = 0 for even n.
For all n >= 1, a(2*n-1) = A055034(2*n-1) = A072451(n).
a(n) = phi(n) - (1/2)*phi(2n), for n>1. - Ridouane Oudra, Jul 13 2023
Sum_{k=1..n} a(k) ~ (1/Pi^2)*n^2. - Amiram Eldar, Jul 15 2023

A349134 Dirichlet inverse of Kimberling's paraphrases, A003602.

Original entry on oeis.org

1, -1, -2, 0, -3, 2, -4, 0, -1, 3, -6, 0, -7, 4, 4, 0, -9, 1, -10, 0, 5, 6, -12, 0, -4, 7, -2, 0, -15, -4, -16, 0, 7, 9, 6, 0, -19, 10, 8, 0, -21, -5, -22, 0, 3, 12, -24, 0, -9, 4, 10, 0, -27, 2, 8, 0, 11, 15, -30, 0, -31, 16, 4, 0, 9, -7, -34, 0, 13, -6, -36, 0, -37, 19, 8, 0, 9, -8, -40, 0, -4, 21, -42, 0, 11, 22
Offset: 1

Views

Author

Antti Karttunen, Nov 13 2021

Keywords

Crossrefs

Programs

  • Mathematica
    k[n_] := (n/2^IntegerExponent[n, 2] + 1)/2; a[1] = 1; a[n_] := a[n] = -DivisorSum[n, a[#]*k[n/#] &, # < n &]; Array[a, 100] (* Amiram Eldar, Nov 13 2021 *)
  • PARI
    up_to = 16384;
    DirInverseCorrect(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = (-u[1]*sumdiv(n, d, if(dA003602(n) = (1+(n>>valuation(n,2)))/2;
    v349134 = DirInverseCorrect(vector(up_to,n,A003602(n)));
    A349134(n) = v349134[n];

Formula

a(1) = 1; a(n) = -Sum_{d|n, d < n} A003602(n/d) * a(d).
a(n) = A349135(n) - A003602(n).

A349371 Inverse Möbius transform of Kimberling's paraphrases (A003602).

Original entry on oeis.org

1, 2, 3, 3, 4, 6, 5, 4, 8, 8, 7, 9, 8, 10, 14, 5, 10, 16, 11, 12, 18, 14, 13, 12, 17, 16, 22, 15, 16, 28, 17, 6, 26, 20, 26, 24, 20, 22, 30, 16, 22, 36, 23, 21, 42, 26, 25, 15, 30, 34, 38, 24, 28, 44, 38, 20, 42, 32, 31, 42, 32, 34, 55, 7, 44, 52, 35, 30, 50, 52, 37, 32, 38, 40, 65, 33, 50, 60, 41, 20, 63, 44, 43
Offset: 1

Views

Author

Antti Karttunen, Nov 15 2021

Keywords

Comments

Dirichlet convolution of sigma (A000203) with A349431, or equally, A264740 with A349447. - Antti Karttunen, Nov 21 2021

Crossrefs

Cf. also A347954, A347955, A347956, A349136, A349370, A349372, A349373, A349374, A349375, A349390, A349431, A349444, A349447 for Dirichlet convolutions of other sequences with A003602.
Cf. also A349393.

Programs

  • Mathematica
    k[n_] := (n / 2^IntegerExponent[n, 2] + 1)/2; a[n_] := DivisorSum[n, k[#] &]; Array[a, 100] (* Amiram Eldar, Nov 16 2021 *)
  • PARI
    A003602(n) = (1+(n>>valuation(n,2)))/2;
    A349371(n) = sumdiv(n,d,A003602(d));

Formula

a(n) = Sum_{d|n} A003602(d).
a(n) = Sum_{d|n} A000203(n/d)*A349431(d) = Sum_{d|n} A264740(n/d)*A349447(d). - Antti Karttunen, Nov 21 2021

A349431 Dirichlet convolution of A003602 (Kimberling's paraphrases) with A055615 (Dirichlet inverse of n).

Original entry on oeis.org

1, -1, -1, -1, -2, 1, -3, -1, -1, 2, -5, 1, -6, 3, 4, -1, -8, 1, -9, 2, 6, 5, -11, 1, -2, 6, -1, 3, -14, -4, -15, -1, 10, 8, 12, 1, -18, 9, 12, 2, -20, -6, -21, 5, 4, 11, -23, 1, -3, 2, 16, 6, -26, 1, 20, 3, 18, 14, -29, -4, -30, 15, 6, -1, 24, -10, -33, 8, 22, -12, -35, 1, -36, 18, 4, 9, 30, -12, -39, 2, -1, 20
Offset: 1

Views

Author

Antti Karttunen, Nov 17 2021

Keywords

Comments

Dirichlet convolution of this sequence with A000010 gives A349136, which also proves the formula involving A023900.
Convolution with A000203 gives A349371.

Crossrefs

Sequence A297381 negated.
Cf. A003602, A023900, A055615, A297381, A349432 (Dirichlet inverse), A349433 (sum with it).
Cf. also A000010, A000203, A349136, A349371, and also A349444, A349447.

Programs

  • Mathematica
    k[n_] := (n / 2^IntegerExponent[n, 2] + 1)/2; a[n_] := DivisorSum[n, # * MoebiusMu [#] * k[n/#] &]; Array[a, 100] (* Amiram Eldar, Nov 18 2021 *)
  • PARI
    A003602(n) = (1+(n>>valuation(n,2)))/2;
    A055615(n) = (n*moebius(n));
    A349431(n) = sumdiv(n,d,A003602(n/d)*A055615(d));
    
  • PARI
    A023900(n) = factorback(apply(p -> 1-p, factor(n)[, 1]));
    A349431(n) = if(!bitand(n,n-1),A023900(n),A023900(n)/2);

Formula

a(n) = Sum_{d|n} A003602(n/d) * A055615(d).
a(n) = A023900(n) when n is a power of 2, and a(n) = A023900(n)/2 for all other numbers.
a(n) = -A297381(n).

A347954 Dirichlet convolution of A003602 with A342001.

Original entry on oeis.org

0, 1, 1, 3, 1, 8, 1, 6, 4, 11, 1, 20, 1, 14, 13, 10, 1, 26, 1, 29, 16, 20, 1, 37, 5, 23, 12, 38, 1, 81, 1, 15, 22, 29, 19, 62, 1, 32, 25, 55, 1, 106, 1, 56, 48, 38, 1, 59, 6, 48, 31, 65, 1, 74, 25, 73, 34, 47, 1, 191, 1, 50, 61, 21, 28, 156, 1, 83, 40, 151, 1, 112, 1, 59, 60, 92, 28, 181, 1, 89, 34, 65, 1, 254, 34
Offset: 1

Views

Author

Antti Karttunen, Sep 20 2021

Keywords

Crossrefs

Programs

Formula

a(n) = Sum_{d|n} A003602(d) * A342001(n/d).

A349390 Dirichlet convolution of A126760 with Kimberling's paraphrases, A003602.

Original entry on oeis.org

1, 2, 3, 3, 5, 6, 7, 4, 8, 10, 10, 9, 12, 14, 17, 5, 15, 16, 17, 15, 24, 20, 20, 12, 28, 24, 22, 21, 25, 34, 27, 6, 35, 30, 47, 24, 32, 34, 42, 20, 35, 48, 37, 30, 50, 40, 40, 15, 54, 56, 53, 36, 45, 44, 71, 28, 60, 50, 50, 51, 52, 54, 71, 7, 84, 70, 57, 45, 71, 94, 60, 32, 62, 64, 100, 51, 99, 84, 67, 25, 63, 70, 70
Offset: 1

Views

Author

Antti Karttunen, Nov 15 2021

Keywords

Crossrefs

Cf. A347233, A347234, A349391, A349392, A349393, A349395, A349431, A349444, A349447 for other Dirichlet convolutions of A126760. And also A349370.

Programs

  • Mathematica
    f[n_] := 2 * Floor[(m = n/2^IntegerExponent[n, 2]/3^IntegerExponent[n, 3])/6] + Mod[m, 3]; k[n_] := (n/2^IntegerExponent[n, 2] + 1)/2; a[n_] := DivisorSum[n, f[#] * k[n/#] &]; Array[a, 100] (* Amiram Eldar, Nov 16 2021 *)
  • PARI
    A003602(n) = (1+(n>>valuation(n,2)))/2;
    A126760(n) = {n&&n\=3^valuation(n, 3)<A126760
    A349390(n) = sumdiv(n,d,A126760(n/d)*A003602(d));

Formula

a(n) = Sum_{d|n} A126760(n/d) * A003602(d).

A349444 Dirichlet convolution of A003602 (Kimberling's paraphrases) with A092673 (Dirichlet inverse of A001511).

Original entry on oeis.org

1, -1, 1, 0, 2, -1, 3, 0, 3, -2, 5, 0, 6, -3, 4, 0, 8, -3, 9, 0, 6, -5, 11, 0, 10, -6, 9, 0, 14, -4, 15, 0, 10, -8, 12, 0, 18, -9, 12, 0, 20, -6, 21, 0, 12, -11, 23, 0, 21, -10, 16, 0, 26, -9, 20, 0, 18, -14, 29, 0, 30, -15, 18, 0, 24, -10, 33, 0, 22, -12, 35, 0, 36, -18, 20, 0, 30, -12, 39, 0, 27, -20, 41, 0, 32
Offset: 1

Views

Author

Antti Karttunen, Nov 18 2021

Keywords

Crossrefs

Cf. A001511, A003602, A008683, A092673, A349445 (Dirichlet inverse), A349446 (sum with it).
Cf. also A349431, A349447.

Programs

  • Mathematica
    s[n_] := MoebiusMu[n] - If[OddQ[n], 0, MoebiusMu[n/2]]; k[n_] := (n/2^IntegerExponent[n, 2] + 1)/2; a[n_] := DivisorSum[n, s[#]*k[n/#] &]; Array[a, 100] (* Amiram Eldar, Nov 19 2021 *)
  • PARI
    A003602(n) = (1+(n>>valuation(n,2)))/2;
    A092673(n) = if(n<1, 0, moebius(n) - if( n%2, 0, moebius(n/2))); \\ From A092673
    A349444(n) = sumdiv(n,d,A003602(n/d)*A092673(d));

Formula

a(n) = Sum_{d|n} A003602(n/d) * A092673(d).

A249814 "Mountains of Eratosthenes" permutation: a(1) = 1, a(n) = A249741(A001511(n), a(A003602(n))).

Original entry on oeis.org

1, 2, 3, 4, 5, 8, 7, 6, 9, 14, 15, 24, 13, 20, 11, 10, 17, 26, 27, 34, 29, 44, 47, 48, 25, 38, 39, 54, 21, 32, 19, 12, 33, 50, 51, 64, 53, 80, 67, 76, 57, 86, 87, 114, 93, 140, 95, 120, 49, 74, 75, 94, 77, 116, 107, 90, 41, 62, 63, 84, 37, 56, 23, 16, 65, 98, 99, 124, 101, 152, 127, 118, 105, 158, 159, 204, 133, 200, 151, 142
Offset: 1

Views

Author

Antti Karttunen, Nov 06 2014

Keywords

Comments

This sequence is a "recursed variant" of A249811.
From Antti Karttunen, Jan 18 2015: (Start)
This can be viewed as an entanglement or encoding permutation where the complementary pairs of sequences to be interwoven together are even and odd numbers (A005843/A005408) which are entangled with another complementary pair: even numbers in the order they appear in A253886 and odd numbers in their usual order: (A253886/A005408).
From the above follows also that this sequence can be represented as a binary tree. Each child to the left is obtained by doubling the parent and subtracting one, and each child to the right is obtained by applying A253886 to the parent:
1
|
...................2...................
3 4
5......../ \........8 7......../ \........6
/ \ / \ / \ / \
/ \ / \ / \ / \
/ \ / \ / \ / \
9 14 15 24 13 20 11 10
17 26 27 34 29 44 47 48 25 38 39 54 21 32 19 12
(End)
For listening I recommend some (mostly) percussive MIDI-instrument and the pitch offset set to at least 29 and the tempo (rate) to about 60. - Antti Karttunen, Feb 17 2015

Crossrefs

Inverse: A249813.
Similar or related permutations: A246684, A249811, A250244, A252755.
Compare also the scatterplot of this sequence to the graphs of A252755 and A246684.
Differs from A246684 for the first time at n=14, where a(14) = 20, while A246684(14) = 26.

Formula

In the following formulas, A083221 and A249741 are interpreted as bivariate functions:
a(1) = 1, for n>1: a(n) = A083221(A001511(n), a(A003602(n))) - 1 = A249741(A001511(n), a(A003602(n))).
a(1) = 1, a(2n) = A253886(a(n)), a(2n+1) = (2*a(n+1))-1. - Antti Karttunen, Jan 18 2015
As a composition of other permutations:
a(n) = A250244(A246684(n)).
Other identities. For all n >= 1, the following holds:
a(n) = (1+a((2*n)-1))/2. [The odd bisection from a(1) onward with one added and then halved gives the sequence back.]
a(A000079(n-1)) = A006093(n).

A347955 Dirichlet convolution of A003415 (arithmetic derivative) with A003602 (Kimberling's paraphrases).

Original entry on oeis.org

0, 1, 1, 5, 1, 8, 1, 17, 8, 11, 1, 32, 1, 14, 13, 49, 1, 44, 1, 47, 16, 20, 1, 100, 13, 23, 44, 62, 1, 81, 1, 129, 22, 29, 19, 156, 1, 32, 25, 151, 1, 106, 1, 92, 86, 38, 1, 276, 18, 92, 31, 107, 1, 206, 25, 202, 34, 47, 1, 301, 1, 50, 111, 321, 28, 156, 1, 137, 40, 151, 1, 460, 1, 59, 120, 152, 28, 181, 1, 423, 206
Offset: 1

Views

Author

Antti Karttunen, Sep 20 2021

Keywords

Crossrefs

Cf. also A347954, A347956.

Programs

Formula

a(n) = Sum_{d|n} A003415(n/d) * A003602(d).

A349447 Dirichlet convolution of A003602 (Kimberling's paraphrases) with A326937 (Dirichlet inverse of A000265).

Original entry on oeis.org

1, 0, -1, 0, -2, 0, -3, 0, -1, 0, -5, 0, -6, 0, 4, 0, -8, 0, -9, 0, 6, 0, -11, 0, -2, 0, -1, 0, -14, 0, -15, 0, 10, 0, 12, 0, -18, 0, 12, 0, -20, 0, -21, 0, 4, 0, -23, 0, -3, 0, 16, 0, -26, 0, 20, 0, 18, 0, -29, 0, -30, 0, 6, 0, 24, 0, -33, 0, 22, 0, -35, 0, -36, 0, 4, 0, 30, 0, -39, 0, -1, 0, -41, 0, 32, 0, 28
Offset: 1

Views

Author

Antti Karttunen, Nov 19 2021

Keywords

Comments

Dirichlet convolution of this sequence with A264740 is A349371.

Crossrefs

Cf. A000265, A003602, A326937, A349448 (Dirichlet inverse).

Programs

  • Mathematica
    k[n_] := (n/2^IntegerExponent[n, 2] + 1)/2; a[n_] := DivisorSum[n, MoebiusMu[#] * # / 2^IntegerExponent[#, 2] * k[n/#] &]; Array[a, 100] (* Amiram Eldar, Nov 19 2021 *)
  • PARI
    A003602(n) = (1+(n>>valuation(n,2)))/2;
    A006519(n) = (1<A055615(n) = (n*moebius(n));
    A326937(n) = (A055615(n)/A006519(n));
    A349447(n) = sumdiv(n,d,A003602(d)*A326937(n/d));

Formula

a(n) = Sum_{d|n} A003602(d) * A326937(n/d).
Showing 1-10 of 154 results. Next