|
| |
|
|
A108369
|
|
Coefficients of x/(1+3*x+3*x^2-x^3).
|
|
1
| |
|
|
0, 1, -3, 6, -8, 3, 21, -80, 180, -279, 217, 366, -2028, 5203, -9159, 9840, 3160, -48159, 144837, -286874, 377952, -128397, -1035539, 3869760, -8631060, 13248361, -9982143, -18429714, 98483932, -250144797, 436552881, -460740320, -177582480, 2351521281
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,3
|
|
|
REFERENCES
| L. E. Dickson, History of the Theory of Numbers. Carnegie Institute Public. 256, Washington, DC, Vol. 1, 1919; Vol. 2, 1920; Vol. 3, 1923, see vol. 2, p. 562.
|
|
|
FORMULA
| x=a(n), z=a(-n-2), y=a(n)+a(n+1), t=a(-1-n)+a(-n-2) is a solution to 2(x^3+z^3)=y^3+t^3.
G.f.: x/(1+3*x+3*x^2-x^3). a(n)=-3a(n-1)-3a(n-2)+a(n-3). a(-1-n)=A108368(n).
|
|
|
PROG
| (PARI) {a(n)=if(n>=0, polcoeff(x/(1+3*x+3*x^2-x^3)+x*O(x^n), n), n=-1-n; polcoeff(x/(1-3*x-3*x^2-x^3)+x*O(x^n), n))}
|
|
|
CROSSREFS
| Sequence in context: A157032 A011334 A200340 * A010621 A096416 A009393
Adjacent sequences: A108366 A108367 A108368 * A108370 A108371 A108372
|
|
|
KEYWORD
| sign
|
|
|
AUTHOR
| Michael Somos, Jun 01 2005
|
| |
|
|
