%I
%S 2,3,4,5,7,9,13,25
%N 1 plus the nth divisor of 24.
%C Also Coxeter number (denoted m(X)) of the Niemeier lattices X whose root systems are of pure Atype according to the ADE classification; see OnoRolenTrebat paper, page 3, Table 1, Pure Atype root systems.
%D J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", SpringerVerlag, 3rd. ed., 1993. Table 16.1, p. 407.
%H Ken Ono, Larry Rolen, Sarah TrebatLeder, <a href="http://arxiv.org/abs/1403.3712">Classical and umbral Moonshine: connections and padic properties</a>, arXiv:1403.7312v1 [math.NT]
%F a(n) = 1 + A018253(n).
%Y Cf. A000521, A007240, A018253, A018623.
%Y A subsequence of A238839.
%K nonn,easy,fini,full
%O 1,1
%A _Omar E. Pol_, Mar 18 2014
