OFFSET
1,5
COMMENTS
Denominators are given in A203811.
Similar to harmonic series, but with signs chosen to minimize the absolute value of the next term.
LINKS
Hugo Pfoertner, Table of n, a(n) for n = 1..200
Hugo Pfoertner, Illustration of A203810(i)/A203811(i) for i<=100
Hugo Pfoertner, Illustration of A203810(i)/A203811(i) for even i, i<=500
EXAMPLE
s(1)=1, to minimize abs(s(2)) 1/2 has to be subtracted. s(2)=1-1/2=1/2. Similar for s(3) and s(4): s(3)=s(2)-1/3=1/2-1/3=1/6, s(4)=1/6-1/4=-1/12. Since s(4) is negative s(5)=s(4)+1/5=-1/12+1/5=7/60. The numerators of s(1)...s(5) are 1, 1, 1, -1, 7 and the corresponding denominators are 1, 2, 6, 12, 60.
CROSSREFS
KEYWORD
sign,frac
AUTHOR
Hugo Pfoertner and Rainer Rosenthal, Jan 06 2012
STATUS
approved