
1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73
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OFFSET

0,4


LINKS

Table of n, a(n) for n=0..74.
Tanya Khovanova, Recursive Sequences
Index entries for linear recurrences with constant coefficients, signature (2, 1).


FORMULA

a(n) = 2*a(n1) a(n2). G.f.: (1+2*x)/(x1)^2.  R. J. Mathar, Feb 11 2010


MATHEMATICA

Range[0, 80]1 (* Harvey P. Dale, Apr 05 2012 *)
LinearRecurrence[{2, 1}, {1, 0}, 75] (* Ray Chandler, Jul 30 2015 *)


PROG

(PARI) a(n)=n1 \\ Charles R Greathouse IV, Aug 26 2011


CROSSREFS

Cf. A000027, A023444, ..., A023482, A022958, ..., A022996, A256958.
Sequence in context: A132086 A136602 A173474 * A099570 A114142 A020725
Adjacent sequences: A023440 A023441 A023442 * A023444 A023445 A023446


KEYWORD

sign,easy


AUTHOR

N. J. A. Sloane.


STATUS

approved

