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

Author

Paul Barry, Mar 01 2011

Keywords

• nonn
• easy

Comments

A factor in the Hankel transform A186941.

Links

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

Programs

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 *)

Formula

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