OFFSET
0,1
COMMENTS
This sequence is the Pierce expansion of the number 3*s(3) - 1 = 0.370827687432918983346475478500709113969827799141493576... where s(u) = Sum_{k>=0) 1/u^(2^k) for u=3 has been considered by N. J. A. Sloane in A004200.
The continued fraction expansion of the number 3*s(3)-1 is essentially A081771.
LINKS
Jeffrey Shallit, Simple continued fractions for some irrational numbers. J. Number Theory 11 (1979), no. 2, 209-217.
FORMULA
a(0) = 2, a(2k+1) = 3^(2^k), a(2k+2) = 3^(2^k) + 1, k >= 0.
EXAMPLE
The Pierce expansion of 0.3708276874329189833 starts as 1/2 - 1/(2*3) + 1/(2*3*4) - 1/(2*3*4*9) + 1/(2*3*4*9*10) - 1/(2*3*4*9*10*81) + ...
MAPLE
L:=[2]: for k from 0 to 6 do: L:=[op(L), 3^(2^k), 3^(2^k)+1]: od: print(L);
PROG
(PARI) a(n) = if (n==0, 2, if (n%2, 3^(2^((n-1)/2)), 3^(2^((n-2)/2))+1)); \\ Michel Marcus, Mar 31 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Kutlwano Loeto, Mar 24 2017
STATUS
approved