1,1

a(n) = 5*4^((n-1)/2)-2 (n odd), 2*4^(n/2)-2 (n even).

Cf. A050250.

Sequence in context: A074370 A088339 A064400 this_sequence A103100 A101726 A034457

Adjacent sequences: A117860 A117861 A117862 this_sequence A117864 A117865 A117866

nonn

Martin Renner (martin.renner(AT)gmx.net), May 02 2006