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A155199
a(n) = 10*a(n-1) + a(n-2), n > 2 ; a(0) = 1, a(1) = 9, a(2) = 90.
1
1, 9, 90, 909, 9180, 92709, 936270, 9455409, 95490360, 964359009, 9739080450, 98355163509, 993290715540, 10031262318909, 101305913904630, 1023090401365209, 10332209927556720, 104345189676932409, 1053784106696880810, 10642186256645740509, 107475646673154285900
OFFSET
0,2
FORMULA
G.f.: (1 - x - x^2)/(1 - 10*x - x^2).
a(n) = Sum_{k=0..n} A155161(n,k)*9^k. - Philippe Deléham, Feb 08 2012
E.g.f.: 1 + 9*exp(5*x)*sinh(sqrt(26)*x)/sqrt(26). - Stefano Spezia, Mar 01 2023
MATHEMATICA
LinearRecurrence[{10, 1}, {1, 9, 90}, 20] (* Harvey P. Dale, Dec 20 2022 *)
CROSSREFS
Sequence in context: A299872 A173480 A052268 * A147841 A036258 A098399
KEYWORD
nonn,easy
AUTHOR
Philippe Deléham, Jan 21 2009
STATUS
approved