0,2

Sixth binomial transform of A108411. Binomial transform of A162558. Inverse binomial transform of A162758.

a(n) = ((3+sqrt(3))*(6+sqrt(3))^n+(3-sqrt(3))*(6-sqrt(3))^n)/6.

G.f.: (1-5*x)/(1-12*x+33*x^2).

(MAGMA) [ n le 2 select 6*n-5 else 12*Self(n-1)-33*Self(n-2): n in [1..20] ];

Cf. A108411 (powers of 3 repeated), A162558, A162758.

Sequence in context: A034354 A015555 A137382 this_sequence A147958 A104454 A019472

Adjacent sequences: A162754 A162755 A162756 this_sequence A162758 A162759 A162760

nonn

Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jul 13 2009