A099915 Expansion of (1+4x)/((1-x)(1-10x)).

1, 15, 155, 1555, 15555, 155555, 1555555, 15555555, 155555555, 1555555555, 15555555555, 155555555555, 1555555555555, 15555555555555, 155555555555555, 1555555555555555, 15555555555555555, 155555555555555555

Offset

0,2

Comments

Partial sums of (1+4x)/(1-10x)={1,14,140,1400,...}

Links

Table of n, a(n) for n=0..17.

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

Formula

a(n)=10^n*14/9-5/9; a(n)=11a(n-1)-10a(n-2), a(0)=1, a(1)=15.

Mathematica

LinearRecurrence[{11, -10}, {1, 15}, 20] (* or *) Accumulate[ CoefficientList[ Series[ (1+4x)/(1-10x), {x, 0, 20}], x]]  (* Harvey P. Dale, Apr 23 2011 *)

Crossrefs

Sequence in context: A006096 A346843 A341918 * A110557 A016304 A016849

Adjacent sequences: A099912 A099913 A099914 * A099916 A099917 A099918

Keyword

easy,nonn

Author

Paul Barry, Oct 30 2004

Status

approved