0,4

H. Bottomley & A. Karttunen Derivations of the formulae for the diagonals of A073345 & A073346.

a(n < 3) = 0, a(3) = 4, a(n) = 1/12 * 2^(n-1) * (2*n^3 + 9*n^2 - 23*n - 78) or a(n) = 2^(n-2) * |A073775(n-3)| from n >= 3 onward.

A073774 := n -> `if`((n < 3), 0, (2^(n-2))*abs(A073775(n-3)));

A073774(n) = A073345(n+3, n). Cf. A014480, A073773, A073775.

Sequence in context: A003360 A083931 A133881 this_sequence A141032 A156084 A000658

Adjacent sequences: A073771 A073772 A073773 this_sequence A073775 A073776 A073777

nonn

Antti Karttunen Aug 11 2002