|
| |
|
|
A104187
|
|
G.f. -(1+x^2+x^4)/((x^3+x^2+x-1)*(x-1)^2).
|
|
1
|
|
|
|
1, 3, 8, 18, 38, 76, 147, 279, 523, 973, 1802, 3328, 6136, 11302, 20805, 38285, 70437, 129575, 238348, 438414, 806394, 1483216, 2728087, 5017763, 9229135, 16975057, 31222030
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
0,2
|
|
|
COMMENTS
|
A floretion-generated sequence involving Tribonacci numbers.
|
|
|
LINKS
|
Table of n, a(n) for n=0..26.
|
|
|
FORMULA
|
a(n+2) - 2*a(n+1) + a(n) = A081172(n+4)
a(n) = (1/2) [A000073(n+3) + A000073(n+6) - 3n - 6 ]. - Ralf Stephan, May 20 2007
a(0)=1, a(1)=3, a(2)=8, a(3)=18, a(4)=38, a(n)=3*a(n-1)-2*a(n-2)- a(n-4)+a(n-5) [From Harvey P. Dale, June 14 2011]
|
|
|
MATHEMATICA
|
CoefficientList[Series[-(1+x^2+x^4)/((x^3+x^2+x-1)*(x-1)^2), {x, 0, 30}], x] (* or *) LinearRecurrence[{3, -2, 0, -1, 1}, {1, 3, 8, 18, 38}, 30] (* From Harvey P. Dale, June 14 2011 *)
|
|
|
PROG
|
Floretion Algebra Multiplication Program, FAMP Code: 1tesforrokseq[A*B] = A = - .5'ii' + .5'jj' + .5'kk' + .5e B = + 'kj', 1vesforrokseq[A*B] = A000004, ForType: 1A.
|
|
|
CROSSREFS
|
Cf. A081172.
Sequence in context: A036642 A000235 A006478 * A051633 A131051 A172265
Adjacent sequences: A104184 A104185 A104186 * A104188 A104189 A104190
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
Creighton Dement (creighton.k.dement(AT)uni-oldenburg.de), Apr 01 2005
|
|
|
EXTENSIONS
|
Definition corrected by Harvey P. Dale, June 14 2011.
|
|
|
STATUS
|
approved
|
| |
|
|
