A190542 7^n - 4^n.

0, 3, 33, 279, 2145, 15783, 113553, 807159, 5699265, 40091463, 281426673, 1973132439, 13824509985, 96821901543, 677954637393, 4746487768119, 33228635602305, 232613334118023, 1628344878433713, 11398620307466199

Offset

0,2

Comments

Length-n words from letters {1,2,...,7} with at least one letter greater than 4. - Joerg Arndt, Jun 02 2011

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..300

Index entries for linear recurrences with constant coefficients, signature (11,-28).

Formula

a(n) = 11*a(n-1) -28*a(n-2).

a(n) = A000420(n) - A000302(n). - Michel Marcus, Feb 26 2014

Maple

A190542:=n->7^n - 4^n; seq(A190542(n), n=0..30); # Wesley Ivan Hurt, Feb 26 2014

Mathematica

Table[7^n - 4^n, {n, 0, 30}] (* Wesley Ivan Hurt, Feb 26 2014 *)
LinearRecurrence[{11, -28}, {0, 3}, 20] (* Harvey P. Dale, Dec 21 2019 *)

Prog

(Magma) [7^n -4^n: n in [0..30]];
(PARI) a(n)=7^n-4^n \\ Charles R Greathouse IV, Jun 02 2011

Crossrefs

Cf. A121213, A016169.

Sequence in context: A206950 A189644 A003129 * A180416 A043038 A274264

Adjacent sequences: A190539 A190540 A190541 * A190543 A190544 A190545

Keyword

nonn,easy

Author

Vincenzo Librandi, Jun 02 2011

Status

approved