A191630 a(n) = floor((-1 + 2^n)/(1 + 2*n)).

0, 0, 1, 1, 2, 4, 8, 15, 26, 48, 89, 163, 303, 564, 1057, 1985, 3744, 7084, 13443, 25575, 48770, 93206, 178481, 342392, 657930, 1266204, 2440322, 4709393, 9099506, 17602324, 34087042, 66076419, 128207978, 248983611, 483939977, 941362695, 1832519379

Offset

1,5

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Mathematica

f[n_] := Floor[(-1 + 2^n)/(2 n + 1)]
Table[f[n], {n, 1, 40}]    (* A191630 *)

Prog

(Magma) [Floor((-1 + 2^n)/(2*n + 1)): n in [1..50]]; // Vincenzo Librandi, Sep 12 2011
(Maxima) A191630(n):=floor((-1+2^n)/(1+2*n))$ makelist(A191630(n), n, 1, 30); /* Martin Ettl, Oct 25 2012 */
(PARI) a(n) = (2^n-1)\(2*n+1); \\ Altug Alkan, Sep 08 2018

Crossrefs

Cf. A191633.

Sequence in context: A003241 A279320 A182844 * A125513 A054174 A239890

Adjacent sequences: A191627 A191628 A191629 * A191631 A191632 A191633

Keyword

nonn

Author

Clark Kimberling, Jun 09 2011

Status

approved