login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A135991
Expansion of x^3*(x-1)^2*(x+1) / (x^6-3*x^5+3*x^4-x+1).
0
0, 0, 1, 0, -1, 0, -3, 0, 2, -1, 9, 0, -3, 6, -26, 2, 2, -25, 74, -16, 10, 89, -210, 85, -67, -288, 599, -375, 291, 869, -1725, 1485, -1112, -2471, 5020, -5479, 4037, 6629, -14732, 19236, -14332, -16629, 43417, -65116, 50320, 37975, -127831, 214397, -175328
OFFSET
1,7
COMMENTS
The ratio is "ringing" cyclic:
Table[N[a[[n]]/a[[n - 1]]], {n, 8, 100}]
The sequence alternates and is relatively low in value a little longer than other such sequences.
FORMULA
G.f.: x^3*(x-1)^2*(x+1) / (x^6-3*x^5+3*x^4-x+1). - Colin Barker, Feb 02 2013
MATHEMATICA
Clear[v, m, n, M0, N0] v[0] = {0, 0, 1}; v[1] = {0, 1, 2}; M0 = {{0, 1, 0}, {0, 0, 1}, {1, 0, 1}}; N0 = {{0, 1, 0}, {0, 0, 1}, {1, 1, 1}}; v[n_] := v[n] = N0.v[n - 1] - M0.v[n - 2] a = Table[v[n][[1]], {n, 0, 100}]
CROSSREFS
Sequence in context: A295041 A359710 A127913 * A331422 A279631 A102003
KEYWORD
sign,easy
AUTHOR
Roger L. Bagula, Mar 03 2008
EXTENSIONS
Better name by Colin Barker, Feb 02 2013
STATUS
approved