login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

Irregular triangle read by rows: similar to A222417, but here only the maximal entries in each set Q(n) are given.
1

%I #19 Mar 06 2013 01:05:08

%S 1,2,2,3,3,4,4,5,6,5,12,7,10,12,7,10,15,24,14,15,18,20,24,14,18,21,24,

%T 40,60,11,18,21,24,28,40,60,11,28,35,36,42,120,13,22,35,36,84,120,13,

%U 22,33,36,90,120,140,168,26,33,44,105,120,140,168,180,26,39,44,55,66,126,140,180,210,240,336,17,39,52,55,72,126,132,180,240,280,336,420

%N Irregular triangle read by rows: similar to A222417, but here only the maximal entries in each set Q(n) are given.

%C See Nussbaum and Verduyn Lunel (1999) and (2003) for precise definition of Q(n). There are in fact several different but equivalent definitions. For example, Q(n) is "intimately connected to the set of periods of periodic points of classes of nonlinear maps defined on the positive cone in R^n" [Nussbaum and Verduyn Lunel (2003)]

%C To obtain A222417, expand each row by including all the divisors of the terms given here.

%D Lemmens, Bas; Nussbaum, Roger. Nonlinear Perron-Frobenius theory. Cambridge Tracts in Mathematics, 189. Cambridge University Press, Cambridge, 2012. xii+323 pp. ISBN: 978-0-521-89881-2 MR2953648

%D Nussbaum, Roger D.; Scheutzow, Michael. Admissible arrays and a nonlinear generalization of Perron-Frobenius theory. J. London Math. Soc. (2) 58 (1998), no. 3, 526--544. MR1678149 (2000b:37013)

%D Nussbaum, R. D.; Verduyn Lunel, S. M. Generalizations of the Perron-Frobenius theorem for nonlinear maps. Mem. Amer. Math. Soc.138 (1999), no. 659, viii+98 pp. MR1470912 (99i:58125). Gives the first 50 rows.

%H Nussbaum, Roger D.; Verduyn Lunel, Sjoerd M., <a href="http://www.math.rutgers.edu/~nussbaum/Pubs/nusslunel2003.pdf">Asymptotic estimates for the periods of periodic points of non-expansive maps</a>, Ergodic Theory Dynam. Systems 23 (2003), no. 4, 1199--1226. See the function Q(n). MR1997973 (2004m:37033).

%e Triangle begins

%e 1,

%e 2,

%e 2, 3,

%e 3, 4,

%e 4, 5, 6,

%e 5, 12,

%e 7, 10, 12,

%e 7, 10, 15, 24,

%e 14, 15, 18, 20, 24,

%e 14, 18, 21, 24, 40, 60,

%e ...

%Y Cf. A222417.

%K nonn,tabf

%O 1,2

%A _N. J. A. Sloane_, Mar 05 2013