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A173776
a(n) = (4*10^n + 41)/9.
2
5, 9, 49, 449, 4449, 44449, 444449, 4444449, 44444449, 444444449, 4444444449, 44444444449, 444444444449, 4444444444449, 44444444444449, 444444444444449, 4444444444444449, 44444444444444449, 444444444444444449
OFFSET
0,1
FORMULA
a(n) = 10*a(n-1) - 41 with n>0, a(0)=5.
G.f.: (5 - 46*x)/((1-x)*(1-10*x)). - Vincenzo Librandi, Jul 05 2012
a(n) = 11*a(n-1) -10*a(n-2). - Vincenzo Librandi, Jul 05 2012
E.g.f.: (1/9)*(41*exp(x) + 4*exp(10*x)). - G. C. Greubel, Jul 06 2021
MATHEMATICA
Join[{5}, FromDigits/@Table[PadLeft[{9}, n, 4], {n, 20}]] (* or *) Join[{5}, NestList[10#-41&, 9, 20]] (* Harvey P. Dale, Feb 17 2012 *)
CoefficientList[Series[(5-46*x)/((1-x)*(1-10*x)), {x, 0, 30}], x] (* Vincenzo Librandi, Jul 05 2012 *)
PROG
(Magma) [(4*10^n+41)/9: n in [0..20]]; // Vincenzo Librandi, Jul 05 2012
(Sage) [(4*10^n + 41)/9 for n in (0..30)] # G. C. Greubel, Jul 06 2021
CROSSREFS
Cf. A093402.
Sequence in context: A100457 A080872 A328333 * A289909 A000324 A123817
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Feb 24 2010
STATUS
approved