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A143095 (1, 2, 4, 8,...) interleaved with (4, 8, 16, 32,...). 7
1, 4, 2, 8, 4, 16, 8, 32, 16, 64, 32, 128, 64, 256, 128, 512, 256, 1024, 512, 2048, 1024, 4096, 2048, 8192, 4096, 16384, 8192, 32768, 16384, 65536, 32768, 131072, 65536, 262144, 131072, 524288, 262144, 1048576, 524288, 2097152, 1048576, 4194304 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Partial sums are in A079360. a(n) = A076736(n+5). - Klaus Brockhaus, Jul 27 2009

LINKS

Table of n, a(n) for n=0..41.

Index entries for linear recurrences with constant coefficients, signature (0,2).

FORMULA

Inverse binomial transform of A048655: (1, 5, 11, 27, 65, 157,...).

a(n)=A135530(n+1). - R. J. Mathar, Aug 02 2008

Contribution from Klaus Brockhaus, Jul 27 2009: (Start)

a(n) = (5-3*(-1)^n)*2^(1/4*(2*n-1+(-1)^n))/2.

a(n) = 2*a(n-2) for n > 1; a(0) = 1, a(1) = 4.

G.f.: (1+4*x)/(1-2*x^2). (End)

a(n+3) = a(n+2)*a(n+1)/a(n). - Reinhard Zumkeller, Mar 04 2011

MATHEMATICA

nn=30; With[{p=2^Range[0, nn]}, Riffle[Take[p, nn-2], Drop[p, 2]]] (* Harvey P. Dale, Oct 03 2011 *)

PROG

(PARI) for(n=0, 41, print1((5-3*(-1)^n)*2^(1/4*(2*n-1+(-1)^n))/2, ", ")) \\ Klaus Brockhaus, Jul 27 2009

(Maxima) A143095(n):=(5-3*(-1)^n)*2^(1/4*(2*n-1+(-1)^n))/2$

makelist(A143095(n), n, 0, 30); /* Martin Ettl, Nov 03 2012 */

CROSSREFS

Cf. A048655.

Sequence in context: A080965 A083703 A066104 * A141073 A261830 A194038

Adjacent sequences:  A143092 A143093 A143094 * A143096 A143097 A143098

KEYWORD

nonn,easy

AUTHOR

Gary W. Adamson & Roger L. Bagula, Jul 23 2008

EXTENSIONS

More terms from Klaus Brockhaus, Jul 27 2009

STATUS

approved

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Last modified August 18 17:55 EDT 2018. Contains 313834 sequences. (Running on oeis4.)