A199489 a(n) = (11*7^n + 1)/6.

2, 13, 90, 629, 4402, 30813, 215690, 1509829, 10568802, 73981613, 517871290, 3625099029, 25375693202, 177629852413, 1243408966890, 8703862768229, 60927039377602, 426489275643213, 2985424929502490, 20897974506517429, 146285821545622002, 1024000750819354013, 7168005255735478090

Offset

0,1

Links

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

Index entries for linear recurrences with constant coefficients, signature (8,-7).

Formula

a(n) = 7*a(n-1) - 1.

a(n) = 8*a(n-1) - 7*a(n-2).

G.f.: (2-3*x)/((1-x)*(1-7*x)).

From Elmo R. Oliveira, May 09 2025: (Start)

E.g.f.: exp(x)*(1 + 11*exp(6*x))/6.

a(n) = A199490(n)/2 = A199491(n)/3 = A199492(n)/6. (End)

Mathematica

(11*7^Range[0, 20]+1)/6 (* or *) LinearRecurrence[{8, -7}, {2, 13}, 20] (* Harvey P. Dale, May 05 2019 *)

Prog

(Magma) [(11*7^n+1)/6: n in [0..30]];

Crossrefs

Cf. A199490, A199491, A199492.

Sequence in context: A074617 A337169 A367785 * A300764 A381147 A209470

Adjacent sequences: A199486 A199487 A199488 * A199490 A199491 A199492

Keyword

nonn,easy

Author

Vincenzo Librandi, Nov 07 2011

Status

approved