

A181175


The "Fi1" sums of the powersof2 triangle A000079


1



1, 2, 40, 320, 21504, 688128, 178257920, 22817013760, 23433341566976, 11997870882291712, 49179307930885816320, 100719222642454151823360, 1650485975228872480767606784, 13520781109074923362448234774528
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OFFSET

0,2


COMMENTS

The a(n) represent the Fi1(n) sums, see A180662, of the powersof2 triangle A000079. We observe that Fi2(2*n) = Fi1(2*n) and Fi2(2*n+1) = 2*Fi1(2*n+1).


LINKS

Table of n, a(n) for n=0..13.


FORMULA

a(2*n+1) = 2^(2*n+1)*a(2*n) and a(2*n+2) = 2^(2*n+2)*((4^(n+2)  1)/(4^(n+1)  1))*a(2*n+1) with a(0) = 1 and a(1) =2.


MAPLE

nmax:=13: a(0):=1: a(1):=2: for n from 0 to nmax/2 do a(2*n+1):= 2^(2*n+1)*a(2*n): a(2*n+2):=2^(2*n+2)*((4^(n+2)  1)/(4^(n+1)  1))*a(2*n+1): od: seq(a(n), n=0..nmax);


CROSSREFS

Sequence in context: A228240 A155977 A092698 * A035604 A180429 A108033
Adjacent sequences: A181172 A181173 A181174 * A181176 A181177 A181178


KEYWORD

easy,nonn


AUTHOR

Johannes W. Meijer, Oct 10 2010


STATUS

approved



