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A064485 Number of ordered pairs a,b of elements in the dihedral group D_2n such that the subgroup generated by the pair a,b is a proper subgroup of D_2n. 0
1, 10, 18, 40, 40, 108, 70, 160, 162, 280, 154, 432 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

FORMULA

a(n) = 4*n^2 - A064400(n) = 4*n^2 - 3*n*phi(n)

CROSSREFS

A064400, A064279.

Sequence in context: A090995 A153360 A189323 * A007938 A007937 A050576

Adjacent sequences:  A064482 A064483 A064484 * A064486 A064487 A064488

KEYWORD

nonn

AUTHOR

Dan Fux (dan.fux(AT)OpenGaia.com or danfux(AT)OpenGaia.com), Oct 03 2001

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Last modified February 14 18:47 EST 2012. Contains 205663 sequences.