A168548 Least number k requiring n iterations to reach 14 using map n -> sum of largest digit of all divisors of n (A168239).

14, 15, 8, 7, 4, 3, 2, 10, 19, 18, 12, 6, 5, 24, 32, 70, 288, 15624, 44031980160

Offset

0,1

Comments

a(19) > 1.67*10^46. [From Donovan Johnson, Jul 06 2010]

References

J. Earls, "Black Hole 14," Mathematical Bliss, Pleroma Publications, 2009, pages 18-22. ASIN: B002ACVZ6O

Links

Table of n, a(n) for n=0..18.

Crossrefs

Sequence in context: A165835 A134913 A176169 * A004455 A142865 A089838

Adjacent sequences: A168545 A168546 A168547 * A168549 A168550 A168551

Keyword

base,more,nonn

Author

Jason Earls, Nov 29 2009

Extensions

a(1) changed from 14 to 15. - R. J. Mathar, Mar 06 2010

a(18) from Donovan Johnson, Jul 06 2010

Added initial term a(0)=14. - M. F. Hasler, May 23 2012

Status

approved