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

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

1,2

Links

Table of n, a(n) for n=1..31.

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

Example

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

Prog

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

Crossrefs

Cf. A008683

Sequence in context: A266791 A052997 A267210 * A265381 A066225 A305777

Adjacent sequences: A074985 A074986 A074987 * A074989 A074990 A074991

Keyword

base,easy,nonn

Author

Benoit Cloitre, Oct 02 2002

Status

approved