A177090 a(n) = a(n-1) + 12*100^(n-1), with a(0)=0.

0, 12, 1212, 121212, 12121212, 1212121212, 121212121212, 12121212121212, 1212121212121212, 121212121212121212, 12121212121212121212, 1212121212121212121212, 121212121212121212121212, 12121212121212121212121212, 1212121212121212121212121212

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..99 [offset shifted by Georg Fischer, Jun 16 2021]

Index entries for linear recurrences with constant coefficients, signature (101,-100).

Formula

a(n) = 12*(100^(n-1)-1)/99 = 12*A094028(n-1) for n>=1. - Jon E. Schoenfield, Jun 24 2010

G.f.: 12*x / ( (100*x-1)*(x-1) ). - R. J. Mathar, Aug 24 2011

Maple

a:= n-> parse(cat(0, 12$n)):
seq(a(n), n=0..20);  # Alois P. Heinz, Jun 16 2021

Mathematica

CoefficientList[Series[12 x /((100 x - 1) (x - 1)), {x, 0, 20}], x] (* Vincenzo Librandi, Jun 13 2014 *)
Table[FromDigits[PadRight[{}, 2n, {1, 2}]], {n, 0, 15}] (* or *) LinearRecurrence[ {101, -100}, {0, 12}, 15] (* Harvey P. Dale, Nov 12 2017 *)

Prog

(Magma) [12*((100^(n-1)-1)/99): n in [1..20]]; // Vincenzo Librandi, Jun 13 2014

Crossrefs

Cf. A094028, A153848.

Sequence in context: A178529 A360502 A201642 * A103269 A317955 A033564

Adjacent sequences: A177087 A177088 A177089 * A177091 A177092 A177093

Keyword

nonn,easy

Author

Vincenzo Librandi, Jun 05 2010

Extensions

Corrected by N. J. A. Sloane, Jun 22 2010

Offset changed to 0 by Georg Fischer, Jun 16 2021

Status

approved