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A007778 n^(n+1). +0
33
0, 1, 8, 81, 1024, 15625, 279936, 5764801, 134217728, 3486784401, 100000000000, 3138428376721, 106993205379072, 3937376385699289, 155568095557812224, 6568408355712890625, 295147905179352825856 (list; graph; listen)
OFFSET

0,3

COMMENT

Number of edges of the complete bipartite graph of order n+n^n, K_n,n^n - Roberto E. Martinez II (remartin(AT)fas.harvard.edu), Jan 07 2002

All rational solutions to the equation x^y = y^x, with x < y, are given by x = A000169(n+1)/A000312(n), y = A000312(n+1)/A007778(n), where n = 1, 2, 3, ... . - Nick Hobson Nov 30 2006

REFERENCES

Clifford A. Pickover, A Passion for Mathematics, Wiley, 2005; see p. 67.

LINKS

N. Hobson, Exponential equation.

FORMULA

E.g.f.: -W(-x)/(1+W(-x))^3, W(x) Lambert's function (principal branch).

MAPLE

a:=n->mul(n, k=0..n): seq(a(n), n=0..16); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jan 26 2008

CROSSREFS

Cf. A000169, A000272, A000312, A007830, A008785-A008791. Essentially the same as A065440.

Sequence in context: A098308 A055996 A068617 this_sequence A065440 A092366 A022519

Adjacent sequences: A007775 A007776 A007777 this_sequence A007779 A007780 A007781

KEYWORD

nonn,easy

AUTHOR

njas

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Last modified July 26 13:41 EDT 2008. Contains 142293 sequences.


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