

A029745


Expansion of (1+2x+6x^2+x^3)/(12x^2).


1



1, 2, 8, 5, 16, 10, 32, 20, 64, 40, 128, 80, 256, 160, 512, 320, 1024, 640, 2048, 1280, 4096, 2560, 8192, 5120, 16384, 10240, 32768, 20480, 65536, 40960, 131072, 81920, 262144, 163840, 524288, 327680, 1048576, 655360, 2097152, 1310720, 4194304
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OFFSET

1,2


COMMENTS

Note that 4 is the only power of 2 not here. All terms are either 2^k or 5*2^k.
Note that 4 is the only power of 2 not here. All terms are either 2^k or 5*2^k.


LINKS

Table of n, a(n) for n=1..41.
Index entries for linear recurrences with constant coefficients, signature (0,2)


FORMULA

G.f.: (1+2x+6x^2+x^3)/(12x^2).


MATHEMATICA

LinearRecurrence[{0, 2}, {1, 2, 8, 5}, 50] (* or *) With[{nn=20}, Join[{1, 2}, Riffle[ 8*2^Range[0, nn], 5 2^Range[0, nn]]]] (* Harvey P. Dale, Sep 28 2016 *)


PROG

(PARI) a(n)=if(n<2, 1+max(1, n), 2^(n\2)*if(n%2, 5/2, 4))


CROSSREFS

Cf. A094958 (numbers of the form 2^n or 5*2^n)
Sequence in context: A182528 A185583 A155901 * A183232 A096417 A274416
Adjacent sequences: A029742 A029743 A029744 * A029746 A029747 A029748


KEYWORD

nonn,easy


AUTHOR

N. J. A. Sloane.


EXTENSIONS

Edited by T. D. Noe, Nov 12 2010


STATUS

approved



