A198969 (11*9^n-1)/2.

5, 49, 445, 4009, 36085, 324769, 2922925, 26306329, 236756965, 2130812689, 19177314205, 172595827849, 1553362450645, 13980262055809, 125822358502285, 1132401226520569, 10191611038685125, 91724499348166129, 825520494133495165

Offset

0,1

Links

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

Index entries for linear recurrences with constant coefficients, signature (10,-9).

Formula

a(n) = 9*a(n-1)+4. a(n) = 10*a(n-1)-9*a(n-2), n>1.

G.f.: (5 - x)/(1 - 10*x + 9*x^2). - Vincenzo Librandi, Jan 03 2013

Mathematica

CoefficientList[Series[(5 - x)/(1 - 10*x + 9*x^2), {x, 0, 30}], x] (* Vincenzo Librandi, Jan 03 2013 *)
LinearRecurrence[{10, -9}, {5, 49}, 20] (* Harvey P. Dale, Oct 16 2021 *)

Prog

(Magma) [(11*9^n-1)/2: n in [0..20]]

Crossrefs

Sequence in context: A293841 A351586 A224756 * A155629 A096596 A001079

Adjacent sequences: A198966 A198967 A198968 * A198970 A198971 A198972

Keyword

nonn,easy

Author

Vincenzo Librandi, Nov 01 2011

Status

approved