|
| |
|
|
A075676
|
|
a(n)=(1/2)(-(-1)^n+1)T(n)+(1/2)((-1)^n+1)S(n), where T(n)=tribonacci numbers A000073, S(n)=generalized tribonacci numbers A001644.
|
|
0
| |
|
|
3, 1, 3, 2, 11, 7, 39, 24, 131, 81, 443, 274, 1499, 927, 5071, 3136, 17155, 10609, 58035, 35890, 196331, 121415, 664183, 410744, 2246915, 1389537, 7601259, 4700770, 25714875, 15902591, 86992799, 53798080, 294294531, 181997601
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,1
|
|
|
COMMENTS
| a(n)=T(n) if n odd, a(n)=S(n) if n even. a(n)=T(n)+((-1)^n+1)T(n-1)+(3/2)((-1)^n+1)T(n-2).
|
|
|
FORMULA
| a(n)=3a(n-2)+a(n-4)+a(n-6), a(0)=3, a(1)=1, a(2)=3, a(3)=2, a(4)=11, a(5)=7. Ogf (3+x-6x^2-x^3-x^4)/(1-3x^2-x^4-x^6).
|
|
|
MATHEMATICA
| CoefficientList[Series[(3+x-6x^2-x^3-x^4)/(1-3x^2-x^4-x^6), {x, 0, 40}], x]
|
|
|
CROSSREFS
| Cf. A000073, A001644, A005013, A005247, A075536.
Sequence in context: A133916 A058589 A112164 * A124814 A122567 A122431
Adjacent sequences: A075673 A075674 A075675 * A075677 A075678 A075679
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Mario Catalani (mario.catalani(AT)unito.it), Sep 24 2002
|
| |
|
|
