1,1

a(n) = 8*7^((n-1)/2)-2 (n odd), 2*7^(n/2)-2 (n even).

Cf. A050250.

Sequence in context: A106692 A032470 A018809 this_sequence A094060 A076722 A076305

Adjacent sequences: A117863 A117864 A117865 this_sequence A117867 A117868 A117869

nonn

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