OFFSET
1,1
COMMENTS
Colton conjectured that T(n) >= pi(n)/2 for all n, i.e., this sequence is nonnegative. Zelinsky proved it for n > 7.42*10^13 (see the Zelinsky reference). This calculation went to 7.44*10^13, proving the conjecture.
LINKS
Simon Colton, Refactorable Numbers - A Machine Invention, J. Integer Sequences, Vol. 2, 1999.
Joshua Zelinsky, Tau Numbers: A Partial Proof of a Conjecture and Other Results , Journal of Integer Sequences, Vol. 5 (2002), Article 02.2.8.
EXAMPLE
For n=6, pi(6)=3, T(6)=2, so a(6) = 2*2 - 3 = 1.
CROSSREFS
KEYWORD
nonn
AUTHOR
Jud McCranie, Jan 11 2019
STATUS
approved