

A165192


a(0) = 1, a(1) = 2, a(3) = 3, a(n) = a(n1)  a(n3).


0



1, 2, 3, 2, 0, 3, 5, 5, 2, 3, 8, 10, 7, 1, 11, 18, 17, 6, 12, 29, 35, 23, 6, 41, 64, 58, 17, 47, 105, 122, 75, 30, 152, 227, 197, 45, 182, 379, 424, 242, 137, 561, 803, 666, 105, 698, 1364, 1469, 771, 593, 2062, 2833, 2240, 178
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OFFSET

0,2


LINKS



FORMULA

G.f.: (1+x+x^2)/(1x+x^3).


EXAMPLE

a(3) = 2 because 2 = 3  1 where the 1, 3 on the right of the equals sign are the first and third terms of the series.


MATHEMATICA

LinearRecurrence[{1, 0, 1}, {1, 2, 3}, 80] (* Harvey P. Dale, Apr 13 2012 *)


PROG

(Python)
series = [1, 2, 3]
for i in range(2, 30):
series.append(series[i]  series[i  2])
print(series)


CROSSREFS



KEYWORD

easy,sign


AUTHOR



EXTENSIONS

Offset corrected and recurrence simplified by R. J. Mathar, Sep 08 2009


STATUS

approved



