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Table of n, a(n) for n=1..53.
Index entries for linear recurrences with constant coefficients, signature (1,0,1,-1).
G.f. x*(1+4*x+x^2+x^3) / ( (1+x+x^2)*(x-1)^2 ). - R. J. Mathar, Dec 03 2011
Sequence in context: A030742 A048583 A169622 * A033158 A193569 A032721
Adjacent sequences: A047318 A047319 A047320 * A047322 A047323 A047324
N. J. A. Sloane.