|
| |
|
|
A164549
|
|
a(n) = 4*a(n-1)+2*a(n-2) for n > 1; a(0) = 1, a(1) = 6.
|
|
3
| |
|
|
1, 6, 26, 116, 516, 2296, 10216, 45456, 202256, 899936, 4004256, 17816896, 79276096, 352738176, 1569504896, 6983495936, 31072993536, 138258966016, 615181851136, 2737245336576, 12179345048576, 54191870867456
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,2
|
|
|
COMMENTS
| Binomial transform of A123011. Inverse binomial transform of A164550.
|
|
|
FORMULA
| a(n) = ((3+2*sqrt(6))*(2+sqrt(6))^n+(3-2*sqrt(6))*(2-sqrt(6))^n)/6.
G.f.: (1+2*x)/(1-4*x-2*x^2).
|
|
|
MATHEMATICA
| Transpose[NestList[Flatten[{Rest[#], ListCorrelate[{2, 4}, #]}]&, {1, 6}, 40]][[1]] (* From Harvey P. Dale, Mar 23 2011 *)
|
|
|
PROG
| (MAGMA) [ n le 2 select 5*n-4 else 4*Self(n-1)+2*Self(n-2): n in [1..22] ];
|
|
|
CROSSREFS
| Cf. A123011, A164550.
Sequence in context: A113991 A145374 A124465 * A046647 A046233 A140231
Adjacent sequences: A164546 A164547 A164548 * A164550 A164551 A164552
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Aug 15 2009
|
| |
|
|
