OFFSET
0,1
COMMENTS
Consider the curve lying between the positive x-axis and the line y=1 and generated by the following process for k = 1, 2, 3, ...: Draw a circular arc about the origin from (sqrt(k-1), 1) down to (sqrt(k), 0), then draw a vertical line segment from there up to (sqrt(k), 1).
After the k-th arc and line segment have been drawn, the length of the curve is k + Sum_{j=1..k} sqrt(j)*arcsin(1/sqrt(j)) = 2k + (1/6)*log(k) + C + (1/120)/k + (13/10080)/k^2 - (37/120960)/k^3 - (617/3548160)/k^4 + (8719/98841600)/k^5 + (47623/553512960)/k^6 - ... where C = 0.561549... is the constant whose decimal expansion consists of the terms of this sequence.
EXAMPLE
0.56154909687269913108487471408627625859911343571650...
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Jon E. Schoenfield, Feb 07 2019
STATUS
approved