|
| |
|
|
A087440
|
|
Expansion of (1-2x-3x^2)/((1-2x)(1-4x)).
|
|
2
| |
|
|
1, 4, 13, 46, 172, 664, 2608, 10336, 41152, 164224, 656128, 2622976, 10488832, 41949184, 167784448, 671113216, 2684403712, 10737516544, 42949869568, 171799085056, 687195553792, 2748780642304, 10995119423488, 43980471402496
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,2
|
|
|
COMMENTS
| Binomial transform is A087439. Second binomial transform of A084221 (with extra leading 1).
|
|
|
FORMULA
| a(n)=5*4^n/8+3*2^n/4-3*0^n/8
a(0)=1, a(1)=4, a(2)=13, a(n)=6*a(n-1)-8*a(n-2) [From Harvey P. Dale, Jan 18 2012]
|
|
|
MATHEMATICA
| CoefficientList[Series[(1-2x-3x^2)/((1-2x)(1-4x)), {x, 0, 30}], x] (* or *) Join[{1}, LinearRecurrence[{6, -8}, {4, 13}, 30]] (* From Harvey P. Dale, Jan 18 2012 *)
|
|
|
CROSSREFS
| Sequence in context: A026641 A149435 A149436 * A149437 A149438 A151448
Adjacent sequences: A087437 A087438 A087439 * A087441 A087442 A087443
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Sep 03 2003
|
| |
|
|
