

A171606


Expressible as A*B^A in two or more different ways


2



648, 2048, 4608, 5184, 41472, 52488, 472392, 500000, 524288, 2654208, 3125000, 4718592, 10125000, 13436928, 21233664, 30233088, 46118408, 76236552, 134217728, 169869312, 344373768, 402653184, 512000000, 648000000, 737894528
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OFFSET

1,1


COMMENTS

For any relatively prime pair A and C, there is an infinite number of solutions A*B^A=C*D^C, with B and D of the form B=C^W*A^X, D=C^Y*A^Z, and W,Y constrained by AW=CY+1 and X,Z constrained by CZ=AX+1. Details and examples on Munafo web page.


LINKS

Table of n, a(n) for n=1..25.
R. Munafo, Generalized Cullen and Woodall Numbers


EXAMPLE

648=3*6^3=2*18^2. 5184=4*6^4=3*12^3. 344373768=8*9^8=3*486^3=2*13122^2. 922640625=5*45^5=3*675^3.


CROSSREFS

Cf. A235368.
Sequence in context: A034281 A157432 A272780 * A006914 A204392 A233677
Adjacent sequences: A171603 A171604 A171605 * A171607 A171608 A171609


KEYWORD

nonn


AUTHOR

Robert Munafo, Dec 12 2009


STATUS

approved



