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A128808
Coefficients of the invariant of degree 20 associated with the icosahedral group.
1
-1, 228, -494, -228, -1
OFFSET
0,2
REFERENCES
A. Erdelyi, Higher Transcendental Functions, McGraw-Hill, 1955, Vol. 3, p. 11.
F. Klein, Lectures on the Icosahedron ..., 2nd Rev. Ed., 1913; reprinted by Dover, NY, 1956; see p. 61.
S. Mukai, An Introduction to Invariants and Moduli, Cambridge, 2003; see p. 19.
EXAMPLE
H = -(x^20 + y^20) + 228*(x^15*y^5 - x^5*y^15) - 494*x^10*y^10.
CROSSREFS
Cf. A128809. The third invariant (which does not have its own entry) is f = x*y*(x^10 + 11*x^5*y^5 - y^10).
Sequence in context: A252228 A252221 A154519 * A043411 A172531 A258557
KEYWORD
sign,fini,full
AUTHOR
N. J. A. Sloane, Apr 10 2007
STATUS
approved