A091409 a(n) is the smallest m such that A090822(m) = n.

1, 3, 9, 220

Offset: 1

Author

N. J. A. Sloane, based on a suggestion from Dion Gijswijt (gijswijt(AT)science.uva.nl), Mar 04 2004

Keywords

• nonn

Links

• Dion C. Gijswijt, Krulgetallen, Pythagoras, 55ste Jaargang, Nummer 3, Jan 2016. (Shows that the sequence is infinite)
• Fokko J. van de Bult, Dion C. Gijswijt, John P. Linderman, N. J. A. Sloane, and Allan R. Wilks, A Slow-Growing Sequence Defined by an Unusual Recurrence, J. Integer Sequences, Vol. 10 (2007), #07.1.2.
• Fokko J. van de Bult, Dion C. Gijswijt, John P. Linderman, N. J. A. Sloane, and Allan R. Wilks, A Slow-Growing Sequence Defined by an Unusual Recurrence [pdf, ps].
• Levi van de Pol, The Growth Rate of Gijswijt's Sequence, J. Int. Seq. (2025) Vol. 28, Art. No. 25.4.6. See p. 2.
• Index entries for sequences related to Gijswijt's sequence

Crossrefs

Cf. A090822.

Formula

a(n) is about 2^(2^(3^(4^(5^...^(n-1))))).

Extensions

Sequence is infinite but next term, about 10^(10^23.09987) (see A091787), is too large to include.