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.

A074587 Sum of the coefficients of the n-th Moebius polynomial, M(n,x), where M(n,-1) = mu(n), the Moebius function of n.

Original entry on oeis.org

1, 3, 7, 18, 37, 85, 171, 364, 736, 1513, 3027, 6168, 12337, 24849, 49743, 99872, 199745, 400322, 800645, 1602862, 3205903, 6414837, 12829675, 25665996, 51332030, 102676401, 205353546, 410732134, 821464269, 1642979927, 3285959855
Offset: 1

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Author

Paul D. Hanna, Aug 25 2002

Keywords

Comments

It seems that a(n+1)>2*a(n). - Benoit Cloitre, Aug 26 2002
a(n+1)=2*a(n)+1 if and only if n+1 is prime. - Benoit Cloitre, Dec 04 2002

Examples

			a(5) = M(5,1) = 1+9+15+10+2 = 37, since M(5,x) = 1 + 9x +15x^2 +10x^3 + 2x^4.
		

Crossrefs

Cf. A074586.
First column of A169659. [From Mats Granvik, Paul D. Hanna, Apr 05 2010]

Programs

  • Mathematica
    m[n_, x_] := m[n, x]=1+x*Sum[m[i, x]Floor[n/i], {i, 1, n-1}]; Table[m[n, 1], {n, 1, 40}]

Formula

a(n) = M(n, 1) (see A074586 for definition of M(n, x)). a(n) mod 2 = A008966(n). a(n) is asymptotic to c*2^n with c=1.530191414016549187154362361492633020259512374111... Benoit Cloitre, Dec 04 2002
a(1)=1 a(n)=1+sum(i=1, n-1, floor(n/i)*a(i)). - Benoit Cloitre, Dec 04 2002

Extensions

Cross reference corrected by Mats Granvik, Apr 23 2010