|
| |
|
|
A080871
|
|
a(n)*a(n+3) - a(n+1)*a(n+2) = 3, given a(0)=a(1)=1, a(2)=4.
|
|
5
| |
|
|
1, 1, 4, 7, 31, 55, 244, 433, 1921, 3409, 15124, 26839, 119071, 211303, 937444, 1663585, 7380481, 13097377, 58106404, 103115431, 457470751, 811826071, 3601659604, 6391493137, 28355806081, 50320119025, 223244789044
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,3
|
|
|
FORMULA
| a(n) = (3 + a(n-1)*a(n-2))/a(n-3) for n>2.
G.f.: (-x^3 - 4*x^2 + x + 1)/(x^4 - 8*x^2 + 1)
a(n+4)=8*a(n+2)-a(n) [From Richard Choulet (richardchoulet(AT)yahoo.fr), Dec 04 2008]
a(n) = (0.25 + sqrt(10)/20)*(sqrt(4 + sqrt(15)))^n + (0.25 + sqrt(10)/20)*(sqrt(4 - sqrt(15)))^n + ( - 1/20*10^(1/2) + 1/4)*( - sqrt(4 + sqrt(15)))^n + ( - 1/20*10^(1/2) + 1/4)*( - (sqrt(4 - sqrt(15))))^n [From Richard Choulet (richardchoulet(AT)yahoo.fr), Dec 06 2008]
|
|
|
CROSSREFS
| Cf. A001519, A079496, A080872, A080873, A080874, A080875.
Bisections are A001091 and A070997.
Sequence in context: A149088 A047004 A030689 * A102666 A123801 A156228
Adjacent sequences: A080868 A080869 A080870 * A080872 A080873 A080874
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Paul D. Hanna (pauldhanna(AT)juno.com), Feb 22 2003
|
| |
|
|
