

A174837


Sequence built as it follows in comments.


1



9, 2, 45, 2, 11, 2, 225, 2, 11, 2, 56, 2, 11, 2, 1125, 2, 11, 2, 56, 2, 11, 281, 2, 11, 2, 56, 2, 11, 2, 5625
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OFFSET

0,1


COMMENTS

If we denote "A" the finite sequence between a(2^(n1)2) and a(2^n2), the subsequence of a between
a(2^(n)2) and a(2^(n+1)2) is given by: " A  a(3*2^(n1)2)  A" for every n>=2.


LINKS

Table of n, a(n) for n=0..29.


FORMULA

a(2n+1)=2. a(2^(n+1)2)=9*5^n. a(3*2^n2)=(9*5^n1)/4.


EXAMPLE

a(4)=a(2*32)=(9*41)/4=11. a(14)=a(2^42)==9*5^3=125*9=1125.
Between a(2) and a(6) the subsequence is "2, 11, 2"; then between a(6) and a(14) the subsequence of a is:
"2, 11, 2, a(10)=56, 2, 11, 2".
It seems that this new sequence gives the number of 2 in the sets of 2 of the sequence A174835.


CROSSREFS

Cf. A174835.
Sequence in context: A152020 A055516 A248314 * A096042 A038292 A294685
Adjacent sequences: A174834 A174835 A174836 * A174838 A174839 A174840


KEYWORD

easy,nonn,uned


AUTHOR

Richard Choulet, Mar 30 2010


STATUS

approved



