A027540 Second diagonal of A027537.

3, 16, 55, 156, 399, 960, 2223, 5020, 11143, 24432, 53079, 114492, 245535, 524032, 1113823, 2358972, 4980375, 10485360, 22019655, 46136860, 96468463, 201326016, 419429775, 872414556, 1811938599, 3758095600, 7784627383, 16106126460, 33285995583, 68719475712

Offset: 2

Author

Olivier Gérard

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 2..1000

Crossrefs

Cf. A027537.

Programs

Magma

[(n+1)*(2^n-n-1): n in [2..30]]; // Vincenzo Librandi, Sep 04 2017

Mathematica

Table[(n + 1) (2^n - n - 1), {n, 2, 35}] (* Vincenzo Librandi, Sep 04 2017 *)

Formula

Numerators of sequence a[ n, n-1 ] in (a[ i, j ])^2 where a[ i, j ] = A(i, j)/i! if j <= i, 0 if j > i.

a(n) = (n+1)*(2^n - n - 1). - Vladeta Jovovic, Aug 18 2002

G.f.: x^2*(-3+5*x)/((2*x-1)^2*(x-1)^3). - Maksym Voznyy (voznyy(AT)mail.ru), Aug 14 2009; corrected by R. J. Mathar, Sep 16 2009

a(n) = Sum_{k=0..n} Sum_{i=0..n} (i-k) * C(n-k,i-2). - Wesley Ivan Hurt, Sep 19 2017

Extensions

More terms from Vladeta Jovovic, Aug 18 2002