|
|
A137483
|
|
a(n+1) = 9*a(n) - 6, a(0) = 2.
|
|
1
|
|
|
2, 12, 102, 912, 8202, 73812, 664302, 5978712, 53808402, 484275612, 4358480502, 39226324512, 353036920602, 3177332285412, 28595990568702, 257363915118312, 2316275236064802, 20846477124583212, 187618294121248902, 1688564647091240112, 15197081823821161002
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,1
|
|
LINKS
|
|
|
FORMULA
|
a(n) = (3+5*9^n)/4.
a(n) = 10*a(n-1)-9*a(n-2) for n>1.
G.f.: 2*(1-4*x) / ((1-x)*(1-9*x)).
(End)
|
|
MATHEMATICA
|
RecurrenceTable[{a[1] == 2, a[n] == 9 a[n-1] - 6}, a, {n, 30}] (* Vincenzo Librandi, Feb 06 2016 *)
|
|
PROG
|
(PARI) Vec(2*(1-4*x)/((1-x)*(1-9*x)) + O(x^25)) \\ Colin Barker, Feb 05 2016
(Magma) [n le 1 select 2 else 9*Self(n-1)-6: n in [1..30]]; // Vincenzo Librandi, Feb 06 2016
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|