A186942 a(n)=2(4^n-n*2^n)-1.

1, 3, 15, 79, 383, 1727, 7423, 30975, 126975, 515071, 2076671, 8343551, 33456127, 134004735, 536412159, 2146500607, 8587837439, 34355281919, 137429516287, 549735890943, 2198981312511, 8796004941823, 35184187539455, 140737102479359, 562949148114943, 2251798135963647

Offset

0,2

Comments

A factor in the Hankel transform A186941.

Links

Table of n, a(n) for n=0..25.

Index entries for linear recurrences with constant coefficients, signature (9,-28,36,-16).

Formula

G.f.: (1-6x+16x^2-8x^3)/((1-2x)^2*(1-5x+4x^2)).

Mathematica

Table[2(4^n-n 2^n)-1, {n, 0, 30}] (* or *) LinearRecurrence[{9, -28, 36, -16}, {1, 3, 15, 79}, 30] (* Harvey P. Dale, Feb 22 2023 *)

Crossrefs

Sequence in context: A299568 A031884 A337284 * A193913 A292097 A052755

Adjacent sequences: A186939 A186940 A186941 * A186943 A186944 A186945

Keyword

nonn,easy

Author

Paul Barry, Mar 01 2011

Status

approved