A036293 a(n) = n * 7^n.

0, 7, 98, 1029, 9604, 84035, 705894, 5764801, 46118408, 363182463, 2824752490, 21750594173, 166095446412, 1259557135291, 9495123019886, 71213422649145, 531726889113616, 3954718737782519, 29311444762388082, 216579008522089717

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (14,-49).

Formula

a(0)=0, a(1)=7, a(n) = 14*a(n-1) - 49*a(n-2). - Harvey P. Dale, Aug 08 2011

G.f.: (7*x)/(7*x-1)^2. - Harvey P. Dale, Aug 08 2011

From Amiram Eldar, Jul 20 2020: (Start)

Sum_{n>=1} 1/a(n) = log(7/6).

Sum_{n>=1} (-1)^(n+1)/a(n) = log(8/7). (End)

Mathematica

Table[n 7^n, {n, 0, 30}] (* or *) LinearRecurrence[{14, -49}, {0, 7}, 31] (* Harvey P. Dale, Aug 08 2011 *)

Prog

(Magma) [n*7^n: n in [0..20]] ; // Vincenzo Librandi, Aug 09 2011

Crossrefs

Sequence in context: A267669 A288681 A124092 * A133679 A219406 A267664

Adjacent sequences: A036290 A036291 A036292 * A036294 A036295 A036296

Keyword

nonn

Author

N. J. A. Sloane

Status

approved