A014937 a(1)=1, a(n)=n*20^(n-1)+a(n-1).

1, 41, 1241, 33241, 833241, 20033241, 468033241, 10708033241, 241108033241, 5361108033241, 118001108033241, 2575601108033241, 55823601108033241, 1202703601108033241, 25778703601108033241, 550066703601108033241

Offset

1,2

Links

Harvey P. Dale, Table of n, a(n) for n = 1..750

Index entries for linear recurrences with constant coefficients, signature (41, -440, 400).

Formula

a(1)=1, a(2)=41, a(3)=1241, a(n)=41*a(n-1)-440*a(n-2)+400*a(n-3) From Harvey P. Dale, Jun 04 2012

G.f.: -x / ( (x-1)*(-1+20*x)^2 ). - R. J. Mathar, Nov 07 2015

Mathematica

RecurrenceTable[{a[1]==1, a[n]==n*20^(n-1)+a[n-1]}, a, {n, 20}] (* or *) LinearRecurrence[{41, -440, 400}, {1, 41, 1241}, 20] (* Harvey P. Dale, Jun 04 2012 *)

Crossrefs

Sequence in context: A196744 A196902 A297349 * A275225 A275145 A118451

Adjacent sequences: A014934 A014935 A014936 * A014938 A014939 A014940

Keyword

nonn,easy

Author

Olivier Gérard

Status

approved