A173807 a(n) = (7*10^n - 43)/9 for n > 0.

3, 73, 773, 7773, 77773, 777773, 7777773, 77777773, 777777773, 7777777773, 77777777773, 777777777773, 7777777777773, 77777777777773, 777777777777773, 7777777777777773, 77777777777777773, 777777777777777773, 7777777777777777773, 77777777777777777773, 777777777777777777773

Offset: 1

Author

Vincenzo Librandi, Feb 25 2010

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..100
• Index entries for linear recurrences with constant coefficients, signature (11,-10).

Crossrefs

Cf. A093165.

Programs

Magma

[(7*10^n-43)/9: n in [1..20]]; // Vincenzo Librandi, Jul 05 2012

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 *)

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