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A140659
a(n) = floor(A140657(n+2)/10).
1
0, 0, 1, 2, 6, 12, 25, 50, 102, 204, 409, 818, 1638, 3276, 6553, 13106, 26214, 52428, 104857, 209714, 419430, 838860, 1677721, 3355442, 6710886, 13421772, 26843545, 53687090, 107374182, 214748364, 429496729, 858993458, 1717986918, 3435973836
OFFSET
0,4
LINKS
FORMULA
a(2n+2) = 4*a(2n)+A000034(n).
a(2n+1) = 2*a(2n).
MATHEMATICA
a[ n_] := If[n < 2, 0, 2 a[n - 1] + If[ EvenQ[n], Mod[n/2, 2, 1], 0]]; (* Michael Somos, Mar 02 2014 *)
PROG
(PARI) f(n) = 2^n+3*(-1)^n; \\ A140657
a(n) = f(n+2)\10; \\ Michel Marcus, Sep 08 2019
CROSSREFS
Cf. A093387.
Sequence in context: A116562 A045925 A128020 * A238462 A099495 A232164
KEYWORD
nonn
AUTHOR
Paul Curtz, Jul 10 2008
EXTENSIONS
Edited and extended by R. J. Mathar, Jul 29 2008
Name corrected by Michel Marcus, Sep 08 2019
STATUS
approved