A080606 Golomb's sequence using even integers.

2, 2, 4, 4, 6, 6, 6, 6, 8, 8, 8, 8, 10, 10, 10, 10, 10, 10, 12, 12, 12, 12, 12, 12, 14, 14, 14, 14, 14, 14, 16, 16, 16, 16, 16, 16, 18, 18, 18, 18, 18, 18, 18, 18, 20, 20, 20, 20, 20, 20, 20, 20, 22, 22, 22, 22, 22, 22, 22, 22, 24, 24, 24, 24, 24, 24, 24, 24, 26, 26, 26, 26, 26

Offset

1,1

Links

Ivan Neretin, Table of n, a(n) for n = 1..10000

Formula

a(n) is asymptotic to tau^(2-tau)*(2n)^(tau-1) and more precisely it seems that a(n) = round(tau^(2-tau)*(2n)^(tau-1)) +(-1, +0 or +1) where tau is the golden ratio.

Example

Read 2,2,4,4,6,6,6,6,8,8,8,8,10,10,10,10,10,10 as (2,2),(4,4),(6,6,6,6),(8,8,8,8),(10,10,10,10,10,10) count occurrences between 2 parentheses, gives 2,2,4,4,6,... which is the sequence itself.

Mathematica

a = {2, 2}; Do[a = Join[a, Array[2i&, a[[i]]]], {i, 2, 13}]; a (* Ivan Neretin, Apr 03 2015 *)

Crossrefs

Cf. A001462, A080605, A080607.

Sequence in context: A257686 A057144 A198332 * A083535 A250983 A070320

Adjacent sequences: A080603 A080604 A080605 * A080607 A080608 A080609

Keyword

nonn

Author

Benoit Cloitre, Feb 25 2003

Status

approved