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A083904 G.f. 1/(1-x) * sum(k>=0, 3^k*x^2^(k+1)/(1+x^2^k)). 0
0, 1, 0, 4, 3, 1, 0, 13, 12, 10, 9, 4, 3, 1, 0, 40, 39, 37, 36, 31, 30, 28, 27, 13, 12, 10, 9, 4, 3, 1, 0, 121, 120, 118, 117, 112, 111, 109, 108, 94, 93, 91, 90, 85, 84, 82, 81, 40, 39, 37, 36, 31, 30, 28, 27, 13, 12, 10, 9, 4, 3, 1, 0, 364, 363, 361, 360 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Distance to next number of form 2^k-1, written down in binary, then interpreted as ternary. Thus the numbers have no 2 in ternary representation.

LINKS

Table of n, a(n) for n=1..67.

Ralf Stephan, Some divide-and-conquer sequences with (relatively) simple ordinary generating functions.

Ralf Stephan, Table of generating functions

FORMULA

a(1)=0, a(2n) = 3a(n)+1, a(2n+1) = 3a(n).

a(n) = 1/2*(3^(floor(log2(n))+1)-1) - A005836(n).

PROG

(PARI) for(n=1, 100, l=ceil(log(n)/log(2)); t=polcoeff(1/(1-x)*sum(k=0, l, 3^k*(x^2^(k+1))/(1+x^2^k)) + O(x^(n+1)), n); print1(t", "))

CROSSREFS

Cf. A005823, A005836.

Sequence in context: A021236 A136590 A117026 * A215861 A195596 A129810

Adjacent sequences:  A083901 A083902 A083903 * A083905 A083906 A083907

KEYWORD

nonn,easy

AUTHOR

Ralf Stephan, Jun 18 2003

STATUS

approved

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Last modified February 25 00:39 EST 2018. Contains 299630 sequences. (Running on oeis4.)