0,2

Integers n>=0 such that a(n) = 3*n is A003714 Fibbinary numbers.

3*x + 6*x^2 + 7*x^3 + 12*x^4 + 15*x^5 + 14*x^6 + 15*x^7 + 24*x^8 + 27*x^9 + ...

(PARI) {a(n) = bitor(n, n<<1)}

(PARI) {a(n) = if( n==0 | n==-1, n, 2 * a(n \ 2) + (n%2) * (2 + (-1)^(n \ 2)))}

A163618(n) = -a(-n).

Sequence in context: A077459 A048717 A022434 this_sequence A047705 A069891 A088146

Adjacent sequences: A163614 A163615 A163616 this_sequence A163618 A163619 A163620

nonn

Michael Somos, Aug 01 2009