A174837 - OEIS

%I #3 Jan 20 2014 22:19:35

%S 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,

%T 2,11,2,5625

%N Sequence built as it follows in comments.

%C If we denote "A" the finite sequence between a(2^(n-1)-2) and a(2^n-2), the subsequence of a between

%C a(2^(n)-2) and a(2^(n+1)-2) is given by: " A - a(3*2^(n-1)-2) - A" for every n>=2.

%F a(2n+1)=2. a(2^(n+1)-2)=9*5^n. a(3*2^n-2)=(9*5^n-1)/4.

%e a(4)=a(2*3-2)=(9*4-1)/4=11. a(14)=a(2^4-2)==9*5^3=125*9=1125.

%e Between a(2) and a(6) the subsequence is "2, 11, 2"; then between a(6) and a(14) the subsequence of a is:

%e "2, 11, 2, a(10)=56, 2, 11, 2".

%e It seems that this new sequence gives the number of 2 in the sets of 2 of the sequence A174835.

%Y Cf. A174835.

%K easy,nonn,uned

%O 0,1

%A _Richard Choulet_, Mar 30 2010