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A047680 Order of cyclic group of diffeomorphism classes of exotic (4n-1)-spheres which bound parallelizable manifolds, for n >= 2. 3
1, 28, 342736, 29398976, 22841912576, 495449389339648, 113828913905979392, 4138783908783021080576, 226044736813811127599528869888, 35882867158508587149623987273728, 5564179808875681941887049052192768, 197363311803624016534960016288517315362816 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

REFERENCES

J. W. Milnor and J. D. Stasheff, Characteristic Classes, Princeton, 1974, p. 285.

LINKS

Table of n, a(n) for n=1..12.

Index entries for sequences related to Bernoulli numbers.

John W. Milnor, Differential Topology Forty-six Years Later, Notices Amer. Math. Soc. 58 (2011), 804-809.

MAPLE

(-1)*2^(2*n-2)*(2^(2*n-1)-1)*numer(bernoulli(4*n)/n);

CROSSREFS

Cf. A001676.

Sequence in context: A119162 A180067 A259365 * A090768 A119180 A088844

Adjacent sequences:  A047677 A047678 A047679 * A047681 A047682 A047683

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified September 15 22:10 EDT 2019. Contains 327088 sequences. (Running on oeis4.)