A166598 a(n) = 5*n - a(n-1), with n>1, a(1)=5.

5, 5, 10, 10, 15, 15, 20, 20, 25, 25, 30, 30, 35, 35, 40, 40, 45, 45, 50, 50, 55, 55, 60, 60, 65, 65, 70, 70, 75, 75, 80, 80, 85, 85, 90, 90, 95, 95, 100, 100, 105, 105, 110, 110, 115, 115, 120, 120, 125, 125, 130, 130, 135, 135, 140, 140, 145, 145, 150, 150, 155, 155

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (1,1,-1).

Formula

G.f.: 5*x/((1+x)*(x-1)^2). - Vincenzo Librandi, Sep 15 2013

From G. C. Greubel, May 18 2016: (Start)

a(n) = a(n-1) + a(n-2) - a(n-3).

E.g.f.: (5/2)*(x*cosh(x) + (1+x)*sinh(x)).

a(n) = 5*A004526(n+1) = 5*A008619(n-1) = 5*A110654(n). (End)

Mathematica

RecurrenceTable[{a[1]==5, a[n]==5n-a[n-1]}, a, {n, 70}] (* or *) Flatten[ {#, #}&/@(5Range[40])] (* Harvey P. Dale, Nov 29 2011 *)
CoefficientList[Series[5 / ((1 + x) (x - 1)^2), {x, 0, 60}], x] (* Vincenzo Librandi, Sep 15 2013 *)
LinearRecurrence[{1, 1, -1}, {5, 5, 10}, 50] (* G. C. Greubel, May 18 2016 *)

Prog

(Magma) [n le 1 select (n+4) else 5*n-Self(n-1): n in [1..70] ]; // Vincenzo Librandi, Sep 14 2013

Crossrefs

Sequence in context: A360996 A003882 A168284 * A066256 A029842 A112436

Adjacent sequences: A166595 A166596 A166597 * A166599 A166600 A166601

Keyword

nonn,easy

Author

Vincenzo Librandi, Oct 18 2009

Extensions

Corrected a(59) by Harvey P. Dale, Nov 29 2011

Status

approved