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A122886
Interlaced merger of A122883, A122884 and A122885.
3
0, 0, 1, 1, 1, 1, 3, 7, 13, 23, 39, 61, 123, 231, 385, 739, 1339, 2185, 4263, 7819, 12853, 24935, 45543, 74677, 145155, 265503, 435721, 846379, 1547347, 2538625, 4932351, 9018835, 14798077, 28749263, 52565151, 86245741
OFFSET
0,7
FORMULA
a(3n) = A122883(n). a(3n+1)= A122884(n). a(3n+2) = A122885(n).
a(n)=4*a(n-3)+11*a(n-6)-2*a(n-9). G.f.: x^2*(1-x)*(2*x^5-x^4+3*x^2+2*x+1)/ ((2*x^3+1)*(1-6*x^3+x^6)). [From R. J. Mathar, Aug 12 2009]
EXAMPLE
The last row of the matrix M^0 defined in the base sequences is 0,0,1, which starts the sequence with 0, 0, 1. The last row of M^1 is [1,1,1] which adds 1, 1, 1, that is a(3) to a(5), to the sequence.
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
Definition replaced by a more precise phrase by the Assoc. Editors of the OEIS, Mar 12 2010.
STATUS
approved