|
| |
|
|
A122583
|
|
a(n) = a(n - 1) - 2*a(n - 2) + a(n - 3) + 3*(-2*a(n - 4) + a(n - 5)).
|
|
2
| |
|
|
1, 1, 1, 1, 1, -3, -7, -3, 5, 25, 45, -3, -107, -191, -175, 253, 1045, 1189, -171, -3547, -7527, -4603, 11497, 33945, 40869, -10487, -141071, -248407, -120131, 421141, 1227961, 1332777, -726439, -5051271, -8369959, -3306635, 16738977, 43110597, 41391949, -33360335, -183387403, -283721435
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,6
|
|
|
COMMENTS
| This recursion is inspired by Ulam's early experiments in derivative recursions.
|
|
|
FORMULA
| G.f.:(-1-7*x^4-x^3-2*x^2)/(-1+3*x^5-6*x^4+x^3-2*x^2+x) [From Maksym Voznyy (voznyy(AT)mail.ru), Aug 11 2009]
|
|
|
MAPLE
| A122583 := proc(n) option remember ; if n <= 5 then 1; else A122583(n-1)-2*A122583(n-2)+A122583(n-3)+3*(-2*A122583(n-4)+A122583(n-5)) ; fi ; end: seq(A122583(n), n=1..80) ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 18 2007
|
|
|
MATHEMATICA
| a[0] = 1; a[1] = 1; a[2] = 1; a[3] = 1; a[4] = 1; a[n_] := a[n] = a[n - 1] - 2*a[n - 2] + a[n - 3] + 3*(-2*a[n - 4] + a[n - 5]); Table[a[n], {n, 0, 30}]
|
|
|
CROSSREFS
| Sequence in context: A101636 A193534 A096247 * A001265 A060443 A020810
Adjacent sequences: A122580 A122581 A122582 * A122584 A122585 A122586
|
|
|
KEYWORD
| sign
|
|
|
AUTHOR
| Roger Bagula (rlbagulatftn(AT)yahoo.com), Sep 19 2006
|
|
|
EXTENSIONS
| Edited by N. J. A. Sloane (njas(AT)research.att.com), Oct 01 2006
More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 18 2007
|
| |
|
|
