A177112 4*(10^n-7).

12, 372, 3972, 39972, 399972, 3999972, 39999972, 399999972, 3999999972, 39999999972, 399999999972, 3999999999972, 39999999999972, 399999999999972, 3999999999999972, 39999999999999972, 399999999999999972

Offset

1,1

Links

Table of n, a(n) for n=1..17.

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

Formula

G.f. 12*x*(1+20*x) / ( (10*x-1)*(x-1) ). - R. J. Mathar, Aug 24 2011

a(n) = 12 *A033175(n-1). - R. J. Mathar, Aug 24 2011

Mathematica

4(10^Range[20]-7) (* or *) LinearRecurrence[{11, -10}, {12, 372}, 20] (* Harvey P. Dale, Nov 22 2019 *)

Crossrefs

Sequence in context: A268550 A235685 A024298 * A081021 A269609 A251590

Adjacent sequences: A177109 A177110 A177111 * A177113 A177114 A177115

Keyword

nonn,easy

Author

Vincenzo Librandi

Status

approved