login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A009986
Powers of 42.
4
1, 42, 1764, 74088, 3111696, 130691232, 5489031744, 230539333248, 9682651996416, 406671383849472, 17080198121677824, 717368321110468608, 30129469486639681536, 1265437718438866624512, 53148384174432398229504
OFFSET
0,2
COMMENTS
Same as Pisot sequences E(1, 42), L(1, 42), P(1, 42), T(1, 42). Essentially same as Pisot sequences E(42, 1764), L(42, 1764), P(42, 1764), T(42, 1764). 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 42-colored compositions of n such that no adjacent parts have the same color. - Milan Janjic, Nov 17 2011
FORMULA
G.f.: 1/(1-42*x). - Philippe Deléham, Nov 24 2008
a(n) = 42^n; a(n) = 42*a(n-1), a(0)=1. - Vincenzo Librandi, Nov 21 2010
MATHEMATICA
42^Range[0, 14] (* Michael De Vlieger, Jan 13 2018 *)
PROG
(Magma)[42^n: n in [0..20]] // Vincenzo Librandi, Nov 21 2010
(PARI) a(n) = 42^n; \\ Michel Marcus, Jan 14 2018
CROSSREFS
Sequence in context: A208368 A207716 A208077 * A041841 A236270 A216703
KEYWORD
nonn,easy
STATUS
approved