1,4

The old entry with this sequence number was a duplicate of A037444.

F. Goebel and R. P. Nederpelt, The number of numerical outcomes of iterated powers, Amer. Math. Monthly, 80 (1971), 1097-1103.

R. K. Guy and J. L. Selfridge, The nesting and roosting habits of the laddered parenthesis. Amer. Math. Monthly 80 (1973), 868-876.

J. Q. Longyear, personal communication.

N. J. A. Sloane and S. Plouffe, The Encyclopedia of Integer Sequences. San Diego, CA: Academic Press, 1995; entry M1139.

Sequence in context: A063457 A157904 A002845 this_sequence A002955 A093951 A137255

Adjacent sequences: A072922 A072923 A072924 this_sequence A072926 A072927 A072928

dead