OFFSET
1,2
REFERENCES
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..1000
Daniel Shanks, The second-order term in the asymptotic expansion of B(x), Mathematics of Computation 18 (1964), pp. 75-86.
FORMULA
a(n) = Integral_{u=1..2^(n-1)} 1/sqrt(log(u)) du. - Based on Alois P. Heinz's Maple program, Alonso del Arte, Oct 24 2014
MAPLE
Digits := 500:
a:= n-> `if`(n=1, 1, round(evalf(int(1/sqrt(ln(u)), u=1..2^(n-1))))):
seq(a(n), n=1..35); # Alois P. Heinz, Dec 26 2010
MATHEMATICA
Table[Floor[Integrate[1/Sqrt[Log[u]], {u, 1, 2^(n - 1)}]], {n, 2, 40}] (* Based on Alois P. Heinz's Maple program, Alonso del Arte, Oct 24 2014 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
a(17) corrected and more terms from Alois P. Heinz, Dec 26 2010
STATUS
approved