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.

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A329445 Dirichlet inverse of A328745.

Original entry on oeis.org

1, -2, -3, 1, -5, 6, -7, 0, 3, 10, -11, -3, -13, 14, 15, 0, -17, -6, -19, -5, 21, 22, -23, 0, 10, 26, -1, -7, -29, -30, -31, 0, 33, 34, 35, 3, -37, 38, 39, 0, -41, -42, -43, -11, -15, 46, -47, 0, 21, -20, 51, -13, -53, 2, 55, 0, 57, 58, -59, 15, -61, 62, -21, 0, 65, -66, -67, -17
Offset: 1

Views

Author

Werner Schulte, Nov 13 2019

Keywords

Comments

Signed version of A182938.

Crossrefs

Programs

  • Python
    from math import prod, comb
    from sympy import factorint
    def A329445(n): return prod(-comb(p,e) if e&1 else comb(p,e) for p,e in factorint(n).items()) # Chai Wah Wu, Dec 23 2022

Formula

Multiplicative with a(p^e) = (-1)^e*binomial(p,e) for prime p and e >= 0.
Dirichlet g.f.: Sum_{n>0} a(n)/n^s = Product_{p prime} (1-p^(-s))^p.
a(n) = A182938(n) * A008836(n) for n > 0.

A182938 If n = Product (p_j^e_j) then a(n) = Product (binomial(p_j, e_j)).

Original entry on oeis.org

1, 2, 3, 1, 5, 6, 7, 0, 3, 10, 11, 3, 13, 14, 15, 0, 17, 6, 19, 5, 21, 22, 23, 0, 10, 26, 1, 7, 29, 30, 31, 0, 33, 34, 35, 3, 37, 38, 39, 0, 41, 42, 43, 11, 15, 46, 47, 0, 21, 20, 51, 13, 53, 2, 55, 0, 57, 58, 59, 15, 61, 62, 21, 0, 65, 66
Offset: 1

Views

Author

Peter Luschny, Jan 16 2011

Keywords

Crossrefs

Programs

  • Haskell
    a182938 n = product $ zipWith a007318'
       (a027748_row n) (map toInteger $ a124010_row n)
    -- Reinhard Zumkeller, Feb 18 2012
  • Maple
    A182938 := proc(n) local e,j; e := ifactors(n)[2]:
    mul (binomial(e[j][1], e[j][2]), j=1..nops(e)) end:
    seq (A182938(n), n=1..100);
  • Mathematica
    a[n_] := Times @@ (Map[Binomial @@ # &, FactorInteger[n], 1]);
    Table[a[n], {n, 1, 100}] (* Kellen Myers, Jan 16 2011 *)
  • PARI
    a(n)=prod(i=1,#n=factor(n)~,binomial(n[1,i],n[2,i])) \\ M. F. Hasler
    
  • PARI
    for(n=1, 100, print1(direuler(p=2, n, (1 + X)^p)[n], ", ")) \\ Vaclav Kotesovec, Mar 28 2025
    

Formula

a(A185359(n)) = 0. - Reinhard Zumkeller, Feb 18 2012
Dirichlet g.f.: Product_{p prime} (1 + p^(-s))^p. - Ilya Gutkovskiy, Oct 26 2019
Conjecture: Sum_{k=1..n} a(k) ~ c * n^2, where c = 0.33754... - Vaclav Kotesovec, Mar 28 2025

Extensions

Given terms checked with new PARI code by M. F. Hasler, Jan 16 2011
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