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.

A074988 Numbers n such that the k-th binary digit of n equals mu(k)^2 for k=1 up to A029837(n+1).

Original entry on oeis.org

1, 3, 7, 14, 29, 59, 119, 238, 476, 953, 1907, 3814, 7629, 15259, 30519, 61038, 122077, 244154, 488309, 976618, 1953237, 3906475, 7812951, 15625902, 31251804, 62503609, 125007218, 250014436, 500028873, 1000057747, 2000115495
Offset: 1

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Author

Benoit Cloitre, Oct 02 2002

Keywords

Examples

			59 = 111011 and mu(1)^2,mu(2)^2,mu(3)^2,mu(4)^2,mu(5)^2,mu(6)^2 = 1,1,1,0,1,1 hence 59 is in the sequence
		

Crossrefs

Programs

  • PARI
    a(n)=sum(i=1,n,moebius(i)^2*2^(n-i))

Formula

a(n+1)=2*a(n)+mu(n+1)^2 a(n)=sum(i=1, n, mu(i)^2*2^(n-i))
a(n)=sum{k=0..n, abs(mu(n-k+1))*2^k}; - Paul Barry, Jul 20 2005