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 1-7 of 7 results.

A353461 Dirichlet convolution of A003602 (Kimberling's paraphrases) with A323881 (the Dirichlet inverse of A126760).

Original entry on oeis.org

1, 0, 1, 0, 1, 0, 1, 0, 3, 0, 2, 0, 2, 0, 3, 0, 3, 0, 3, 0, 4, 0, 4, 0, 2, 0, 9, 0, 5, 0, 5, 0, 7, 0, 1, 0, 6, 0, 8, 0, 7, 0, 7, 0, 9, 0, 8, 0, 5, 0, 11, 0, 9, 0, 1, 0, 12, 0, 10, 0, 10, 0, 12, 0, 2, 0, 11, 0, 15, 0, 12, 0, 12, 0, 10, 0, 3, 0, 13, 0, 27, 0, 14, 0, 2, 0, 19, 0, 15, 0, 4, 0, 20, 0, 3, 0, 16, 0, 21
Offset: 1

Views

Author

Antti Karttunen, Apr 20 2022

Keywords

Comments

Taking the Dirichlet convolution between this sequence and A349393 gives A349371, and similarly for many other such analogous pairs.

Crossrefs

Cf. A003602, A126760, A323881, A353460 (Dirichlet inverse), A353462 (sum with it).
Cf. also A349371, A349393.

Programs

  • PARI
    up_to = 65537;
    A003602(n) = (1+(n>>valuation(n,2)))/2;
    A126760(n) = {n&&n\=3^valuation(n, 3)<A126760
    DirInverseCorrect(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = (-u[1])*sumdiv(n, d, if(dA126760(n)));
    A323881(n) = v323881[n];
    A353461(n) = sumdiv(n,d,A003602(d)*A323881(n/d));

Formula

a(n) = Sum_{d|n} A003602(d) * A323881(n/d).
a(n) = A353462(n) - A353460(n).

A126760 a(0) = 0, a(2n) = a(n), a(3n) = a(n), a(6n+1) = 2n + 1, a(6n+5) = 2n + 2.

Original entry on oeis.org

0, 1, 1, 1, 1, 2, 1, 3, 1, 1, 2, 4, 1, 5, 3, 2, 1, 6, 1, 7, 2, 3, 4, 8, 1, 9, 5, 1, 3, 10, 2, 11, 1, 4, 6, 12, 1, 13, 7, 5, 2, 14, 3, 15, 4, 2, 8, 16, 1, 17, 9, 6, 5, 18, 1, 19, 3, 7, 10, 20, 2, 21, 11, 3, 1, 22, 4, 23, 6, 8, 12, 24, 1, 25, 13, 9, 7, 26, 5, 27, 2, 1, 14, 28, 3, 29, 15, 10, 4, 30, 2
Offset: 0

Views

Author

N. J. A. Sloane, Feb 19 2007

Keywords

Comments

For further information see A126759, which provided the original motivation for this sequence.
From Antti Karttunen, Jan 28 2015: (Start)
The odd bisection of the sequence gives A253887, and the even bisection gives the sequence itself.
A254048 gives the sequence obtained when this sequence is restricted to A007494 (numbers congruent to 0 or 2 mod 3).
For all odd numbers k present in square array A135765, a(k) = the column index of k in that array. (End)
A322026 and this sequence (without the initial zero) are ordinal transforms of each other. - Antti Karttunen, Feb 09 2019
Also ordinal transform of A065331 (after the initial 0). - Antti Karttunen, Sep 08 2024

Crossrefs

One less than A126759.
Cf. A347233 (Möbius transform) and also A349390, A349393, A349395 for other Dirichlet convolutions.
Ordinal transform of A065331 and of A322026 (after the initial 0).
Related arrays: A135765, A254102.

Programs

  • Mathematica
    f[n_] := Block[{a}, a[0] = 0; a[1] = a[2] = a[3] = 1; a[x_] := Which[EvenQ@ x, a[x/2], Mod[x, 3] == 0, a[x/3], Mod[x, 6] == 1, 2 (x - 1)/6 + 1, Mod[x, 6] == 5, 2 (x - 5)/6 + 2]; Table[a@ i, {i, 0, n}]] (* Michael De Vlieger, Feb 03 2015 *)
  • PARI
    A126760(n)={n&&n\=3^valuation(n,3)<M. F. Hasler, Jan 19 2016

Formula

a(n) = A126759(n)-1. [The original definition.]
From Antti Karttunen, Jan 28 2015: (Start)
a(0) = 0, a(2n) = a(n), a(3n) = a(n), a(6n+1) = 2n + 1, a(6n+5) = 2n + 2.
Or with the last clause represented in another way:
a(0) = 0, a(2n) = a(n), a(3n) = a(n), a(6n+1) = 2n + 1, a(6n-1) = 2n.
Other identities. For all n >= 1:
a(n) = A253887(A003602(n)).
a(6n-3) = a(4n-2) = a(2n-1) = A253887(n).
(End)
a(n) = A249746(A003602(A064989(n))). - Antti Karttunen, Feb 04 2015
a(n) = A323882(4*n). - Antti Karttunen, Apr 18 2022

Extensions

Name replaced with an independent recurrence and the old description moved to the Formula section - Antti Karttunen, Jan 28 2015

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).

A347233 Möbius transform of A126760.

Original entry on oeis.org

1, 0, 0, 0, 1, 0, 2, 0, 0, 0, 3, 0, 4, 0, 0, 0, 5, 0, 6, 0, 0, 0, 7, 0, 7, 0, 0, 0, 9, 0, 10, 0, 0, 0, 8, 0, 12, 0, 0, 0, 13, 0, 14, 0, 0, 0, 15, 0, 14, 0, 0, 0, 17, 0, 14, 0, 0, 0, 19, 0, 20, 0, 0, 0, 16, 0, 22, 0, 0, 0, 23, 0, 24, 0, 0, 0, 20, 0, 26, 0, 0, 0, 27, 0, 22, 0, 0, 0, 29, 0, 24, 0, 0, 0, 24, 0, 32
Offset: 1

Views

Author

Antti Karttunen, Aug 26 2021

Keywords

Crossrefs

Cf. A000004, A349339 (even and odd bisection).

Programs

  • Mathematica
    f[n_] := 2 * Floor[(m = n/2^IntegerExponent[n, 2]/3^IntegerExponent[n, 3])/6] + Mod[m, 3]; a[n_] := DivisorSum[n, f[#] * MoebiusMu[n/#] &]; Array[a, 100] (* Amiram Eldar, Nov 16 2021 *)
  • PARI
    A126760(n) = {n&&n\=3^valuation(n, 3)<A126760
    A347233(n) = sumdiv(n,d,moebius(n/d)*A126760(d));

Formula

a(n) = Sum_{d|n} A008683(n/d) * A126760(d).

A323882 Sum of A126760 and its Dirichlet inverse.

Original entry on oeis.org

2, 0, 0, 1, 0, 2, 0, 1, 1, 4, 0, 1, 0, 6, 4, 1, 0, 1, 0, 2, 6, 8, 0, 1, 4, 10, 1, 3, 0, 0, 0, 1, 8, 12, 12, 1, 0, 14, 10, 2, 0, 0, 0, 4, 2, 16, 0, 1, 9, 14, 12, 5, 0, 1, 16, 3, 14, 20, 0, 2, 0, 22, 3, 1, 20, 0, 0, 6, 16, 12, 0, 1, 0, 26, 14, 7, 24, 0, 0, 2, 1, 28, 0, 3, 24, 30, 20, 4, 0, 2, 30, 8, 22, 32, 28, 1, 0, 25, 4, 9, 0, 0, 0, 5, 12
Offset: 1

Views

Author

Antti Karttunen, Feb 08 2019

Keywords

Comments

From Antti Karttunen, Aug 18 2021: (Start)
No negative terms in range 1 .. 2^20.
Apparently zeros occur only on (some of the) positions given by A030059, with exceptions for example on n = 70, 105, 110, 130, 154, etc, where a(n) > 0.
(End)

Crossrefs

Programs

  • PARI
    up_to = 20000;
    A126760(n) = {n&&n\=3^valuation(n, 3)<A126760
    DirInverseCorrect(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = (-u[1])*sumdiv(n, d, if(dA126760(n)));
    A323881(n) = v323881[n];
    A323882(n) = (A126760(n)+A323881(n));

Formula

a(n) = A126760(n) + A323881(n).
For n > 1, a(n) = -Sum_{d|n, 1A126760(d) * A323881(n/d). - Antti Karttunen, Aug 18 2021

A323886 Dirichlet inverse of A004718, Per Nørgård's "infinity sequence".

Original entry on oeis.org

1, 1, -2, 0, 0, -2, -3, 0, 2, 0, -1, 0, 1, -3, -4, 0, 0, 2, -3, 0, 11, -1, -2, 0, -3, 1, 0, 0, 2, -4, -5, 0, 2, 0, -1, 0, 1, -3, -8, 0, -1, 11, -2, 0, 16, -2, -3, 0, 10, -3, -4, 0, -2, 0, -1, 0, 8, 2, 1, 0, 3, -5, -26, 0, 0, 2, -3, 0, 7, -1, -2, 0, -3, 1, 12, 0, 8, -8, -5, 0, -5, -1, -2, 0, 0, -2, -11, 0, -2, 16, -7, 0, 21, -3, -4, 0, -3, 10, 0, 0, 2, -4, -5, 0
Offset: 1

Views

Author

Antti Karttunen, Feb 08 2019

Keywords

Comments

The composer Per Nørgård's name is also written in the OEIS as Per Noergaard.

Crossrefs

Programs

  • Mathematica
    b[0] = 0;
    b[n_?EvenQ] := b[n] = -b[n/2];
    b[n_] := b[n] = b[(n - 1)/2] + 1;
    a[n_] := a[n] = If[n == 1, 1, -Sum[b[n/d] a[d], {d, Most@ Divisors[n]}]];
    Array[a, 100] (* Jean-François Alcover, Feb 16 2020 *)
  • PARI
    up_to = 65537;
    A004718list(up_to) = { my(v=vector(up_to)); v[1]=1; v[2]=-1; for(n=3, up_to, v[n] = if(n%2, v[n>>1]+1, -v[n/2])); (v); }; \\ After code in A004718.
    DirInverseCorrect(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = (-u[1])*sumdiv(n, d, if(dA004718list(up_to));
    A323886(n) = v323886[n];

A323883 Dirichlet inverse of A322026.

Original entry on oeis.org

1, -2, -3, 0, -1, 7, -1, 2, 2, 2, -1, 0, -1, 2, 3, -1, -1, -6, -1, 0, 3, 2, -1, -11, 0, 2, 3, 0, -1, -7, -1, -1, 3, 2, 1, -1, -1, 2, 3, -2, -1, -7, -1, 0, -2, 2, -1, 7, 0, 0, 3, 0, -1, -9, 1, -2, 3, 2, -1, 0, -1, 2, -2, 3, 1, -7, -1, 0, 3, -2, -1, 20, -1, 2, 0, 0, 1, -7, -1, 1, -6, 2, -1, 0, 1, 2, 3, -2, -1, 6, 1, 0, 3, 2, 1, 8
Offset: 1

Views

Author

Antti Karttunen, Feb 08 2019

Keywords

Crossrefs

Programs

  • PARI
    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; };
    A007814(n) = valuation(n,2);
    A007949(n) = valuation(n,3);
    v322026 = rgs_transform(vector(up_to, n, [A007814(n), A007949(n)]));
    DirInverse(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = -sumdiv(n, d, if(dA323883(n) = v323883[n];
Showing 1-7 of 7 results.