A321131 Values of m (mod 25), where A317905(m) = 1. Values of m (mod 25) such that V(m) = 1, where V(m) indicates the constant convergence speed of the tetration base m.

2, 3, 4, 6, 8, 9, 11, 12, 13, 14, 16, 17, 19, 21, 22, 23

Offset: 2

Author

Marco Ripà, Oct 27 2018

Keywords

• nonn
• fini
• full

Comments

This sequence represents the values of the base a such that a^^m, where ^^ indicates tetration or hyper-4 (e.g., 3^^4=3^(3^(3^3))), is characterized by a unitary convergence speed.

64% of the positive integers belong to this list (see A317905).

Examples

			For m = 47, m (mod 25) == 22 and 22^^n has a unitary convergence speed, since A317905(m = 47) = 1 = A317905(m = 22).
		

References

• Marco Ripà, La strana coda della serie n^n^...^n, Trento, UNI Service, Nov 2011. ISBN 978-88-6178-789-6

Links

• Marco Ripà, On the constant congruence speed of tetration, Notes on Number Theory and Discrete Mathematics, Volume 26, 2020, Number 3, pp. 245—260.
• Marco Ripà, The congruence speed formula, Notes on Number Theory and Discrete Mathematics, 2021, 27(4), 43-61.
• Marco Ripà and Luca Onnis, Number of stable digits of any integer tetration, Notes on Number Theory and Discrete Mathematics, 2022, 28(3), 441-457.
• Wikipedia, Tetration

Crossrefs

Cf. A067251, A317824, A317903, A317905, A321130.