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.

Previous Showing 11-20 of 20 results.

A341834 Dirichlet g.f.: 1 / zeta(s)^8.

Original entry on oeis.org

1, -8, -8, 28, -8, 64, -8, -56, 28, 64, -8, -224, -8, 64, 64, 70, -8, -224, -8, -224, 64, 64, -8, 448, 28, 64, -56, -224, -8, -512, -8, -56, 64, 64, 64, 784, -8, 64, 64, 448, -8, -512, -8, -224, -224, 64, -8, -560, 28, -224, 64, -224, -8, 448, 64, 448, 64, 64, -8, 1792
Offset: 1

Views

Author

Ilya Gutkovskiy, Feb 21 2021

Keywords

Comments

Dirichlet inverse of A111218.

Crossrefs

Programs

  • Mathematica
    a[1] = 1; a[n_] := Times @@ ((-1)^#[[2]] Binomial[8, #[[2]]] &/@ FactorInteger[n]); Table[a[n], {n, 60}]
  • PARI
    for(n=1, 100, print1(direuler(p=2, n, (1 - X)^8)[n], ", ")) \\ Vaclav Kotesovec, Feb 22 2021

Formula

Multiplicative with a(p^e) = (-1)^e * binomial(8, e).
a(1) = 1; a(n) = -Sum_{d|n, d < n} tau_8(n/d) * a(d).

A341835 Dirichlet g.f.: 1 / zeta(s)^9.

Original entry on oeis.org

1, -9, -9, 36, -9, 81, -9, -84, 36, 81, -9, -324, -9, 81, 81, 126, -9, -324, -9, -324, 81, 81, -9, 756, 36, 81, -84, -324, -9, -729, -9, -126, 81, 81, 81, 1296, -9, 81, 81, 756, -9, -729, -9, -324, -324, 81, -9, -1134, 36, -324, 81, -324, -9, 756, 81, 756, 81, 81
Offset: 1

Views

Author

Ilya Gutkovskiy, Feb 21 2021

Keywords

Comments

Dirichlet inverse of A111219.

Crossrefs

Programs

  • Mathematica
    a[1] = 1; a[n_] := Times @@ ((-1)^#[[2]] Binomial[9, #[[2]]] &/@ FactorInteger[n]); Table[a[n], {n, 58}]
  • PARI
    for(n=1, 100, print1(direuler(p=2, n, (1 - X)^9)[n], ", ")) \\ Vaclav Kotesovec, Feb 22 2021

Formula

Multiplicative with a(p^e) = (-1)^e * binomial(9, e).
a(1) = 1; a(n) = -Sum_{d|n, d < n} tau_9(n/d) * a(d).

A341836 Dirichlet g.f.: 1 / zeta(s)^10.

Original entry on oeis.org

1, -10, -10, 45, -10, 100, -10, -120, 45, 100, -10, -450, -10, 100, 100, 210, -10, -450, -10, -450, 100, 100, -10, 1200, 45, 100, -120, -450, -10, -1000, -10, -252, 100, 100, 100, 2025, -10, 100, 100, 1200, -10, -1000, -10, -450, -450, 100, -10, -2100, 45, -450, 100, -450
Offset: 1

Views

Author

Ilya Gutkovskiy, Feb 21 2021

Keywords

Comments

Dirichlet inverse of A111220.

Crossrefs

Programs

  • Mathematica
    a[1] = 1; a[n_] := Times @@ ((-1)^#[[2]] Binomial[10, #[[2]]] &/@ FactorInteger[n]); Table[a[n], {n, 52}]
  • PARI
    for(n=1, 100, print1(direuler(p=2, n, (1 - X)^10)[n], ", ")) \\ Vaclav Kotesovec, Feb 22 2021

Formula

Multiplicative with a(p^e) = (-1)^e * binomial(10, e).
a(1) = 1; a(n) = -Sum_{d|n, d < n} tau_10(n/d) * a(d).

A346148 Square array read by descending antidiagonals: T(n, k) = mu^n(k) where mu^1(k) = mu(k) = A008683(k) and for each n >= 1, mu^(n+1)(k) is the Dirichlet convolution of mu(k) and mu^n(k).

Original entry on oeis.org

1, -1, 1, -1, -2, 1, 0, -2, -3, 1, -1, 1, -3, -4, 1, 1, -2, 3, -4, -5, 1, -1, 4, -3, 6, -5, -6, 1, 0, -2, 9, -4, 10, -6, -7, 1, 0, 0, -3, 16, -5, 15, -7, -8, 1, 1, 1, -1, -4, 25, -6, 21, -8, -9, 1, -1, 4, 3, -4, -5, 36, -7, 28, -9, -10, 1, 0, -2, 9, 6, -10, -6
Offset: 1

Views

Author

Sebastian Karlsson, Aug 20 2021

Keywords

Examples

			  n\k| 1    2    3    4    5    6    7    8    9   10   11    12 ...
  ---+--------------------------------------------------------------
   1 | 1   -1   -1    0   -1    1   -1    0    0    1   -1     0 ...
   2 | 1   -2   -2    1   -2    4   -2    0    1    4   -2    -2 ...
   3 | 1   -3   -3    3   -3    9   -3   -1    3    9   -3    -9 ...
   4 | 1   -4   -4    6   -4   16   -4   -4    6   16   -4   -24 ...
   5 | 1   -5   -5   10   -5   25   -5  -10   10   25   -5   -50 ...
   6 | 1   -6   -6   15   -6   36   -6  -20   15   36   -6   -90 ...
   7 | 1   -7   -7   21   -7   49   -7  -35   21   49   -7  -147 ...
   8 | 1   -8   -8   28   -8   64   -8  -56   28   64   -8  -224 ...
   9 | 1   -9   -9   36   -9   81   -9  -84   36   81   -9  -324 ...
  10 | 1  -10  -10   45  -10  100  -10 -120   45  100  -10  -450 ...
  11 | 1  -11  -11   55  -11  121  -11 -165   55  121  -11  -605 ...
  12 | 1  -12  -12   66  -12  144  -12 -220   66  144  -12  -792 ...
  13 | 1  -13  -13   78  -13  169  -13 -286   78  169  -13 -1014 ...
  14 | 1  -14  -14   91  -14  196  -14 -364   91  196  -14 -1274 ...
  15 | 1  -15  -15  105  -15  225  -15 -455  105  225  -15 -1575 ...
  ...
		

Crossrefs

Main diagonal gives A341837.

Programs

  • Mathematica
    T[n_, k_] := If[k == 1, 1, Product[(-1)^e Binomial[n, e], {e, FactorInteger[k][[All, 2]]}]];
    Table[T[n-k+1, k], {n, 1, 12}, {k, n, 1, -1}] // Flatten (* Jean-François Alcover, Sep 13 2021 *)
  • PARI
    T(n, k) = my(f=factor(k)); for (k=1, #f~, f[k,1] = binomial(n, f[k,2])*(-1)^f[k,2]; f[k,2]=1); factorback(f); \\ Michel Marcus, Aug 21 2021
  • Python
    from sympy import binomial, primefactors as pf, multiplicity as mult
    from math import prod
    def T(n, k):
        return prod((-1)**mult(p, k)*binomial(n, mult(p, k)) for p in pf(k))
    

Formula

If k = Product (p_j^m_j) then T(n, k) = Product (binomial(n, m_j)*(-1)^m_j).
Dirichlet g.f. of the n-th row: 1/zeta^n(s).
T(n, p) = -n.
T(n, n) = A341837(n).

A158523 Moebius transform of negated primes in factorization of n.

Original entry on oeis.org

1, -3, -4, 6, -6, 12, -8, -12, 12, 18, -12, -24, -14, 24, 24, 24, -18, -36, -20, -36, 32, 36, -24, 48, 30, 42, -36, -48, -30, -72, -32, -48, 48, 54, 48, 72, -38, 60, 56, 72, -42, -96, -44, -72, -72, 72, -48, -96, 56, -90, 72, -84, -54, 108, 72, 96, 80, 90, -60, 144, -62, 96, -96, 96, 84, -144, -68, -108, 96, -144
Offset: 1

Views

Author

Jaroslav Krizek, Mar 20 2009

Keywords

Examples

			a(72) = a(2^3*3^2) = (-1)^3*(2+1)*2^(3-1) * (-1)^2*(3+1)*3^(2-1) = (-12)*12 = -144.
		

Crossrefs

Programs

  • Mathematica
    f[p_, e_] := (-1)^e*(p + 1)*p^(e - 1); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Jan 05 2023 *)
  • PARI
    a(n) = {my(f = factor(n)); prod(i = 1, #f~, (-1)^f[i,2]*(f[i,1]+1)*f[i,1]^(f[i,2]-1));} \\ Amiram Eldar, Jan 05 2023

Formula

Multiplicative with a(p^e) = (-1)^e*(p+1)*p^(e-1), e>0. a(1)=1.
a(n) = mu(n) * A061019(n) = A008683(n) * A061019(n) = A061020(n) * A007427(n) = A061020(n) * A007428(n) * A000012(n) = A007427(n) * A000012(n) * A061019(n) = A007428(n) * A000005(n) * A061019(n), where operation * denotes Dirichlet convolution. Dirichlet convolution of functions b(n), c(n) is function a(n) = b(n) * c(n) = Sum_{d|n} b(d)*c(n/d).
Inverse Moebius transform gives A061019.
a(n) = (-1)^A001222(n)*A001615(n).
Apparently the Dirichlet inverse of A048250. - R. J. Mathar, Jul 15 2010
Dirichlet g.f.: zeta(2*s-2)/(zeta(s-1)*zeta(s)). - Amiram Eldar, Jan 05 2023

Extensions

More terms from Antti Karttunen, Nov 26 2024

A007432 Moebius transform applied thrice to natural numbers.

Original entry on oeis.org

1, -1, 0, 1, 2, 0, 4, 1, 3, -2, 8, 0, 10, -4, 0, 2, 14, -3, 16, 2, 0, -8, 20, 0, 13, -10, 8, 4, 26, 0, 28, 4, 0, -14, 8, 3, 34, -16, 0, 2, 38, 0, 40, 8, 6, -20, 44, 0, 31, -13, 0, 10, 50, -8, 16, 4, 0, -26, 56, 0, 58, -28, 12, 8, 20, 0, 64, 14
Offset: 1

Views

Author

Keywords

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A007431.

Programs

  • Mathematica
    a[p_, e_] := Sum[ (-1)^k*Binomial[3, k]*p^(e - k), {k, 0, Min[e, 3]}]; a[n_] := Times @@ Apply[a, FactorInteger[n], {1}]; a[1] = 1; Table[ a[n], {n, 1, 68}] (* Jean-François Alcover, Dec 28 2011, after formula *)

Formula

Multiplicative with a(p^e) = Sum_{k=0..3} (-1)^k C(3,k)*p^(e-k)[e>=k];
Dirichlet g.f.: zeta(s-1)/zeta^3(s).
a(n) = Sum{d|n} tau_{-3}(d)*n/d = Sum{d|n} tau_{-2}(d)*phi(n/d), where tau_{-3} is A007428 and tau_{-2} is A007427. - Enrique Pérez Herrero, Jan 19 2013
Sum_{k=1..n} a(k) ~ 108 * n^2 / Pi^6. - Vaclav Kotesovec, Nov 04 2018

A326415 Dirichlet g.f.: zeta(2*s) / zeta(s)^3.

Original entry on oeis.org

1, -3, -3, 4, -3, 9, -3, -4, 4, 9, -3, -12, -3, 9, 9, 4, -3, -12, -3, -12, 9, 9, -3, 12, 4, 9, -4, -12, -3, -27, -3, -4, 9, 9, 9, 16, -3, 9, 9, 12, -3, -27, -3, -12, -12, 9, -3, -12, 4, -12, 9, -12, -3, 12, 9, 12, 9, 9, -3, 36, -3, 9, -12, 4, 9, -27, -3, -12, 9, -27, -3, -16, -3, 9, -12
Offset: 1

Views

Author

Ilya Gutkovskiy, Oct 18 2019

Keywords

Comments

Moebius transform applied twice to A008836.
Dirichlet inverse of A048691.

Crossrefs

Programs

  • Mathematica
    Table[Sum[MoebiusMu[n/d] (-1)^PrimeOmega[d] 2^PrimeNu[d], {d, Divisors[n]}], {n, 1, 75}]
    a[n_] := If[n == 1, n, -Sum[If[d < n, DivisorSigma[0, (n/d)^2] a[d], 0], {d, Divisors[n]}]]; Table[a[n], {n, 1, 75}]
    f[p_, e_] := If[e == 1, -3, (-1)^e*4]; a[1] = 1; a[n_] := Times @@ (f @@@ FactorInteger[n]); Array[a, 100] (* Amiram Eldar, Oct 26 2020 *)

Formula

a(n) = Sum_{d|n} mu(n/d) * (-1)^bigomega(d) * 2^omega(d), where mu = A008683, bigomega = A001222 and omega = A001221.
a(1) = 1; a(n) = -Sum_{d|n, dA000005.
a(n) = Sum_{d|n} A008836(n/d) * A007427(d).
a(n) = Sum_{d|n} A010052(n/d) * A007428(d).
Multiplicative with a(p^e) = -3 if e = 1, and 4*(-1)^e otherwise. - Amiram Eldar, Oct 26 2020
b(n) = abs( a(n) ) is multiplicative with b(p) = 3 and b(p^e) = 4 for e > 1 and prime p. Its Dirichlet g.f. is: zeta(s)^3 / zeta(2*s)^2. - Werner Schulte, Jan 18 2023

A326814 Dirichlet g.f.: (1/zeta(s)) * Product_{p prime} (1 - 2 * p^(-s)).

Original entry on oeis.org

1, -3, -3, 2, -3, 9, -3, 0, 2, 9, -3, -6, -3, 9, 9, 0, -3, -6, -3, -6, 9, 9, -3, 0, 2, 9, 0, -6, -3, -27, -3, 0, 9, 9, 9, 4, -3, 9, 9, 0, -3, -27, -3, -6, -6, 9, -3, 0, 2, -6, 9, -6, -3, 0, 9, 0, 9, 9, -3, 18, -3, 9, -6, 0, 9, -27, -3, -6, 9, -27, -3, 0, -3, 9, -6
Offset: 1

Views

Author

Ilya Gutkovskiy, Oct 19 2019

Keywords

Comments

Moebius transform applied twice to A076479 (unitary Moebius function).

Crossrefs

Cf. A001221, A007428, A008683, A046099 (positions of 0's), A076479, A182139 (Dirichlet inverse), A226177, A326415, A326815.

Programs

  • Mathematica
    Table[Sum[MoebiusMu[n/d] MoebiusMu[d] 2^PrimeNu[d], {d, Divisors[n]}], {n, 1, 75}]
    f[p_, e_] := Which[e == 1, -3, e == 2, 2, e > 2, 0]; a[1] = 1; a[n_] := Times @@ (f @@@ FactorInteger[n]); Array[a, 100] (* Amiram Eldar, Oct 26 2020 *)
  • PARI
    a(n) = sumdiv(n, d, moebius(n/d)*moebius(d)*2^omega(d)); \\ Michel Marcus, Oct 26 2020
    
  • PARI
    for(n=1, 100, print1(direuler(p=2, n, (1 - 2*X)*(1 - X))[n], ", ")) \\ Vaclav Kotesovec, Aug 22 2021

Formula

a(n) = Sum_{d|n} mu(n/d) * mu(d) * 2^omega(d), where mu = A008683 and omega = A001221.
Multiplicative with a(p^e) = -3 if e = 1, 2 if e = 2, and 0 otherwise. - Amiram Eldar, Oct 26 2020

A341837 If n = Product (p_j^k_j) then a(n) = Product ((-1)^k_j * binomial(n, k_j)).

Original entry on oeis.org

1, -2, -3, 6, -5, 36, -7, -56, 36, 100, -11, -792, -13, 196, 225, 1820, -17, -2754, -19, -3800, 441, 484, -23, 48576, 300, 676, -2925, -10584, -29, -27000, -31, -201376, 1089, 1156, 1225, 396900, -37, 1444, 1521, 395200, -41, -74088, -43, -41624, -44550
Offset: 1

Views

Author

Ilya Gutkovskiy, Feb 21 2021

Keywords

Crossrefs

Programs

  • Mathematica
    a[1] = 1; a[n_] := Times @@ ((-1)^#[[2]] Binomial[n, #[[2]]] &/@ FactorInteger[n]); Table[a[n], {n, 45}]
  • PARI
    a(n) = my(f=factor(n)[,2]); prod(k=1, #f, (-1)^f[k]*binomial(n, f[k])); \\ Michel Marcus, Feb 21 2021

Formula

a(n) = A346148(n, n). - Sebastian Karlsson, Aug 22 2021

A127173 T(n,k) = A007427(n/k) if k divides n, T(n,k) = 0 otherwise.

Original entry on oeis.org

1, -2, 1, -2, 0, 1, 1, -2, 0, 1, -2, 0, 0, 0, 1, 4, -2, -2, 0, 0, 1, -2, 0, 0, 0, 0, 0, 1, 0, 1, 0, -2, 0, 0, 0, 1, 1, 0, -2, 0, 0, 0, 0, 0, 1, 4, -2, 0, 0, -2, 0, 0, 0, 0, 1, -2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -2, 4, 1, -2, 0, -2, 0, 0, 0, 0, 0, 1
Offset: 1

Views

Author

Gary W. Adamson, Jan 06 2007

Keywords

Examples

			First few rows of the triangle:
   1;
  -2,  1;
  -2,  0,  1;
   1, -2,  0,  1;
  -2,  0,  0,  0,  1;
   4, -2, -2,  0,  0, 1;
  -2,  0,  0,  0,  0, 0, 1;
   0,  1,  0, -2,  0, 0, 0, 1;
   1,  0, -2,  0,  0, 0, 0, 0, 1;
   4, -2,  0,  0, -2, 0, 0, 0, 0, 1;
  ...
		

Crossrefs

Row sums are A008683.
Column 1 is A007427.

Programs

  • PARI
    \\ here b(n) is A007427(n).
    b(n)={sumdiv(n, d, moebius(d) * moebius(n/d))}
    T(n,k)={if(n%k==0, b(n/k), 0)} \\ Andrew Howroyd, Feb 20 2022

Formula

Square of A054525 as lower triangular matrix.
A007431(n) = Sum_{k=1, n} k*T(n,k).
A007428(n) = Sum_{k=1..n} mu(k)*T(n,k).

Extensions

Missing a(10)-a(14) and a(56) and beyond from Andrew Howroyd, Feb 20 2022
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