A124075 a(n) = 2^(3^(4^...^n)...).

2, 8, 2417851639229258349412352

Offset: 2

Author

David Applegate and N. J. A. Sloane, Nov 08 2006

Keywords

• nonn
• bref

Comments

The next term is too large to include.

The next term, a(5) = 2^(3^(4^5)), has 1.124...*10^488 digits. - Amiram Eldar, Jul 13 2025

Examples

			a(4) = 2^(3^4) = 2417851639229258349412352.
		

References

• David Applegate, Marc LeBrun and N. J. A. Sloane, Descending Dungeons and Iterated Base-Changing, in "The Mathematics of Preference, Choice and Order: Essays in Honor of Peter Fishburn", edited by Steven Brams, William V. Gehrlein and Fred S. Roberts, Springer, 2009, pp. 393-402.

Links

• David Applegate, Marc LeBrun and N. J. A. Sloane, Descending Dungeons and Iterated Base-Changing, arXiv:math/0611293 [math.NT], 2006-2007.
• David Applegate, Marc LeBrun, N. J. A. Sloane, Descending Dungeons, Problem 11286, Amer. Math. Monthly, 116 (2009) 466-467.

Crossrefs

Cf. A014221, A049384, A121263, A121265, A121295, A121296.

Programs

Mathematica

a[n_] := Fold[#2^#1&, n, Range[2, n-1] // Reverse];
Table[a[n], {n, 2, 4}] (* Jean-François Alcover, Oct 10 2018 *)