A198694 a(n) = 7*4^n-1.

6, 27, 111, 447, 1791, 7167, 28671, 114687, 458751, 1835007, 7340031, 29360127, 117440511, 469762047, 1879048191, 7516192767, 30064771071, 120259084287, 481036337151, 1924145348607, 7696581394431, 30786325577727, 123145302310911, 492581209243647, 1970324836974591

Offset

0,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (5,-4).

Formula

a(n) = 4*a(n-1)+3.

a(n) = 5*a(n-1)-4*a(n-2), n>1.

G.f.: ( 6-3*x ) / ( (4*x-1)*(x-1) ). - R. J. Mathar, Oct 30 2011

E.g.f.: exp(x)*(7*exp(3*x) - 1). - Stefano Spezia, Apr 17 2024

Mathematica

7*4^Range[0, 30]-1 (* or *) LinearRecurrence[{5, -4}, {6, 27}, 30] (* Harvey P. Dale, Nov 14 2018 *)

Prog

(Magma) [7*4^n-1: n in [0..30]]

Crossrefs

Cf. A024036, A097743, A114569, A156760.

Sequence in context: A108958 A005284 A371965 * A220101 A014825 A141844

Adjacent sequences: A198691 A198692 A198693 * A198695 A198696 A198697

Keyword

nonn,easy

Author

Vincenzo Librandi, Oct 29 2011

Status

approved