|
| |
|
|
A086972
|
|
a(n) = n*3^(n-1) + (3^n+1)/2.
|
|
3
|
|
|
|
1, 3, 11, 41, 149, 527, 1823, 6197, 20777, 68891, 226355, 738113, 2391485, 7705895, 24712007, 78918989, 251105873, 796364339, 2518233179, 7942120025, 24988621541, 78452649023, 245818300271, 768835960421, 2400651060089
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
0,2
|
|
|
COMMENTS
|
Binomial transform of A057711 (without leading zero). Second binomial transform of (1,1,3,3,5,5,7,7,9,9,11,11,...).
|
|
|
LINKS
|
Vincenzo Librandi, Table of n, a(n) for n = 0..400
Index entries for linear recurrences with constant coefficients, signature (7,-15,9).
|
|
|
FORMULA
|
G.f.: (1-4*x+5*x^2)/((1-x)*(1-3*x)^2).
a(n) = A027471(n) + A007051(n).
|
|
|
PROG
|
(Magma) [n*3^(n-1) + (3^n+1)/2: n in [0..30]]; // Vincenzo Librandi, Jun 09 2011
(PARI) Vec((1-4*x+5*x^2)/((1-x)*(1-3*x)^2) + O(x^40)) \\ Michel Marcus, Mar 08 2016
|
|
|
CROSSREFS
|
Equals (1/2)* (A081038(n) + 1).
Partial sums of A199923.
Sequence in context: A075276 A242233 A294504 * A218348 A320827 A335793
Adjacent sequences: A086969 A086970 A086971 * A086973 A086974 A086975
|
|
|
KEYWORD
|
easy,nonn
|
|
|
AUTHOR
|
Paul Barry, Jul 26 2003
|
|
|
STATUS
|
approved
|
| |
|
|
