

A074988


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


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
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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^(ni))
a(n)=sum{k=0..n, abs(mu(nk+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^(ni))


CROSSREFS

Cf. A008683
Sequence in context: A157672 A125899 A052997 * A066225 A139817 A173010
Adjacent sequences: A074985 A074986 A074987 * A074989 A074990 A074991


KEYWORD

base,easy,nonn


AUTHOR

Benoit Cloitre, Oct 02 2002


STATUS

approved



