0,2

A133603 is a companion sequence.

A133080 * A000108, where A133080 = an infinite lower triangular matrix and A000108 = the Catalan sequence as a vector. For even indexed terms, a(n) = C(n). For odd indexed terms a(n) = C(n) + C(n-1).

a(4) = C(4) = 14.

a(5) = 56 = C(5) + C(4) = 42 + 14.

Cf. A097806, A133080, A000108, A133603.

Sequence in context: A162460 A061274 A061575 this_sequence A137249 A051769 A049955

Adjacent sequences: A133599 A133600 A133601 this_sequence A133603 A133604 A133605

nonn

Gary W. Adamson (qntmpkt(AT)yahoo.com), Sep 18 2007