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A173807
a(n) = (7*10^n - 43)/9 for n > 0.
1
3, 73, 773, 7773, 77773, 777773, 7777773, 77777773, 777777773, 7777777773, 77777777773, 777777777773, 7777777777773, 77777777777773, 777777777777773, 7777777777777773, 77777777777777773, 777777777777777773, 7777777777777777773, 77777777777777777773, 777777777777777777773
OFFSET
1,1
FORMULA
a(n) = 10*a(n-1) + 43 for n > 0, a(0)=-4.
From Vincenzo Librandi, Jul 05 2012: (Start)
G.f.: x*(3+40*x)/((1-x)*(1-10*x)).
a(n) = 11*a(n-1) - 10*a(n-2) for n > 2. (End)
E.g.f.: 4 + exp(x)*(7*exp(9*x) - 43)/9. - Elmo R. Oliveira, Sep 09 2024
MATHEMATICA
CoefficientList[Series[(3+40*x)/((1-x)*(1-10*x)), {x, 0, 30}], x] (* Vincenzo Librandi, Jul 05 2012 *)
Table[FromDigits[PadLeft[{3}, n, 7]], {n, 20}] (* or *) NestList[10#+43&, 3, 20] (* Harvey P. Dale, Dec 05 2013 *)
PROG
(Magma)[(7*10^n-43)/9: n in [1..20]]; // Vincenzo Librandi, Jul 05 2012
CROSSREFS
Cf. A093165.
Sequence in context: A256144 A060883 A162601 * A093165 A189306 A363984
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Feb 25 2010
STATUS
approved