A173768 a(n) = (4*10^n-31)/9.

1, 41, 441, 4441, 44441, 444441, 4444441, 44444441, 444444441, 4444444441, 44444444441, 444444444441, 4444444444441, 44444444444441, 444444444444441, 4444444444444441, 44444444444444441, 444444444444444441

Offset

1,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..100

Index entries for linear recurrences with constant coefficients, signature (11,-10).

Formula

a(n)=10*a(n-1)+31, n>1.

G.f.: x*(1+30*x) / ( (10*x-1)*(x-1) ).

Mathematica

NestList[10#+31&, 1, 20] (* or *) Table[FromDigits[PadLeft[{1}, n, 4]], {n, 20}] (* Harvey P. Dale, May 28 2013 *)
Table[(4 10^n - 31)/9, {n, 1, 30}] (* Vincenzo Librandi, Aug 20 2014 *)

Prog

(Magma) [(4*10^n-31)/9: n in [1..20]]; // Vincenzo Librandi, Aug 20 2014

Crossrefs

Cf. A093174.

Sequence in context: A209823 A196784 A112748 * A061643 A209842 A211154

Adjacent sequences: A173765 A173766 A173767 * A173769 A173770 A173771

Keyword

nonn,easy

Author

Vincenzo Librandi, Feb 24 2010

Status

approved