A009983 Powers of 39.

1, 39, 1521, 59319, 2313441, 90224199, 3518743761, 137231006679, 5352009260481, 208728361158759, 8140406085191601, 317475837322472439, 12381557655576425121, 482880748567480579719, 18832349194131742609041, 734461618571137961752599, 28644003124274380508351361

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Comments

Same as Pisot sequences E(1, 39), L(1, 39), P(1, 39), T(1, 39). Essentially same as Pisot sequences E(39, 1521), L(39, 1521), P(39, 1521), T(39, 1521). See A008776 for definitions of Pisot sequences.

The compositions of n in which each natural number is colored by one of p different colors are called p-colored compositions of n. For n >= 1, a(n) equals the number of 39-colored compositions of n such that no adjacent parts have the same color. - Milan Janjic, Nov 17 2011

Links

• T. D. Noe, Table of n, a(n) for n = 0..100
• Tanya Khovanova, Recursive Sequences.
• Index entries for linear recurrences with constant coefficients, signature (39).

Crossrefs

Cf. A000244, A001022, A008776, A063941.

Programs

Magma

[39^n: n in [0..20]]; // Vincenzo Librandi, Nov 21 2010

Mathematica

39^Range[0,20] (* Harvey P. Dale, Dec 02 2010 *)

PARI

a(n)=39^n \\ Charles R Greathouse IV, Nov 18 2011

Formula

G.f.: 1/(1-39*x). - Philippe Deléham, Nov 24 2008

a(n) = 39^n; a(n) = 39*a(n-1), a(0)=1. - Vincenzo Librandi, Nov 21 2010

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

E.g.f.: exp(39*x).

a(n) = A063941(n)/17 = A000244(n)*A001022(n). (End)