A276780 a(n) = floor(log_10(1/error(n))), where error(n) is the error in the n-th iteration of the quartic Borwein-Borwein algorithm for computing 1/Pi.

9, 41, 171, 694, 2790, 11172, 44702, 178825, 715319, 2861297, 11445210, 45780865, 183123485, 301029988, 301029988

Offset

1,1

References

J. M. Borwein and P. B. Borwein, Pi and the AGM, Wiley, 1987.

Links

Table of n, a(n) for n=1..15.

D. H. Bailey, J. M. Borwein, P. B. Borwein, and S. Plouffe, The Quest for Pi, Mathematical Intelligencer, vol. 19, no. 1 (Jan. 1997), 50-57.

Lucas A. Brown, Python program.

Shalosh B. Ekhad, Three New Sequences for the OEIS, in Fond Memory of Jon Borwein (1951-2016)

Doron Zeilberger, Jonathan Borwein (1951-2016), a PiONEER of Experimental Mathematics, Experimental Mathematics Seminar, Rutgers University, Sep 15 2016.

Crossrefs

Cf. A276778, A276779.

Sequence in context: A201275 A056243 A083584 * A183916 A199311 A146239

Adjacent sequences: A276777 A276778 A276779 * A276781 A276782 A276783

Keyword

nonn,hard,more

Author

Doron Zeilberger, Sep 18 2016

Extensions

Revised definition and terms a(9)-a(15) from Lucas A. Brown, May 05 2023

Status

approved