A155598 a(n) = 7^n-2^n+1.

1, 6, 46, 336, 2386, 16776, 117586, 823416, 5764546, 40353096, 282474226, 1977324696, 13841283106, 96889002216, 678223056466, 4747561477176, 33232930504066, 232630513856136, 1628413597648306, 11398895184848856

Offset: 0

Author

Mohammad K. Azarian, Jan 25 2009

Keywords

• nonn
• easy

Links

• Index entries for linear recurrences with constant coefficients, signature (10,-23,14).

Crossrefs

Cf. A074501, A020515, A155588, A155590, A155592, A155593, A155594, A155596, A155597.

Programs

Mathematica

Table[7^n-2^n+1,{n,0,20}] (* or *) LinearRecurrence[{10,-23,14},{1,6,46},20] (* Harvey P. Dale, Feb 28 2013 *)

PARI

a(n)=7^n-2^n+1 \\ Charles R Greathouse IV, Sep 24 2015

Formula

G.f.: 1/(1-7*x)-1/(1-2*x)+1/(1-x). E.g.f.: e^(7*x)-e^(2*x)+e^x.

a(n) = 9*a(n-1)-14*a(n-2)+6 with a(0)=1, a(1)=6 - Vincenzo Librandi, Jul 21 2010

a(0)=1, a(1)=6, a(2)=46, a(n) = 10*a(n-1)-23*a(n-2)+14*a(n-3). - Harvey P. Dale, Feb 28 2013

a(n) = A190540(n)+1. - R. J. Mathar, Mar 10 2022