A380137 The conjectured maximum multiplicative persistence for bases b >= 2.

1, 3, 3, 6, 5, 8, 6, 7, 11, 13, 7, 15, 13, 11, 8, 17, 10, 18, 14, 14, 14, 19, 9

Offset

2,2

Comments

Data from the T. Lamont-Smith article (see the Links section), Chapter 4, Multi-digit numbers, Table 5.

Links

Table of n, a(n) for n=2..24.

T. Lamont-Smith, Multiplicative Persistence and Absolute Multiplicative Persistence, Journal of Integer Sequences, Vol. 24 (2021), Article 21.6.7.

Example

For n = 277777788888899 (the least number with the multiplicative persistence 11) in the base b = 10: 277777788888899 -> 4996238671872 -> 438939648 -> 4478976 -> 338688 -> 27648 -> 2688 -> 768 -> 336 -> 54 -> 20 -> 0. The upper bound of the multiplicative persistence for the base 10 is conjectured to be 11.

Crossrefs

Cf. A007954, A031346, A031347.

Sequence in context: A318514 A355413 A369857 * A071047 A265008 A165606

Adjacent sequences: A380134 A380135 A380136 * A380138 A380139 A380140

Keyword

nonn,base,more

Author

Ctibor O. Zizka, Jan 13 2025

Status

approved