A057617 - OEIS

%I #11 Feb 02 2018 08:52:58

%S 1,1,1,28,2,992,1,8128,2,130816

%N Order of subgroup bP_{m+1} of group Theta_m of h-cobordism classes of smooth homotopy m-spheres defined by those homotopy m-spheres which bound parallelizable (m+1)-manifolds, where m = 2n+1.

%C a(1) = 1 because the Poincaré conjecture is true.

%D M. A. Kervaire and J. W. Milnor, Groups of homotopy spheres: I. Ann. of Math. (2) 77 1963 504-537.

%D J. P. Levine, Lectures on groups of homotopy spheres. In Algebraic and geometric topology (New Brunswick, NJ, 1983), 62-95, Lecture Notes in Math., 1126, Springer, Berlin, 1985.

%H John W. Milnor, <a href="http://www.ams.org/notices/201106/rtx110600804p.pdf">Differential Topology Forty-six Years Later</a>, Notices Amer. Math. Soc. 58 (2011), 804-809.

%Y Cf. A001676.

%K nonn

%O 0,4

%A _N. J. A. Sloane_, Feb 03 2002

%E a(0)-a(1) from _Andrey Zabolotskiy_, Feb 02 2018