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

2,1

Links

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

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

Mathematica

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

Prog

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

Crossrefs

Cf. A027537.

Sequence in context: A055194 A190730 A173052 * A099851 A005550 A210323

Adjacent sequences: A027537 A027538 A027539 * A027541 A027542 A027543

Keyword

nonn,easy

Author

Olivier Gérard

Extensions

More terms from Vladeta Jovovic, Aug 18 2002

Status

approved