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A192599 Let N = pq (p<q) = A006881(n). Then a(n) = | (p^2-q)(q-1)/2 |. 1
1, 2, 9, 8, 6, 35, 54, 10, 104, 54, 135, 24, 209, 64, 70, 90, 350, 405, 72, 154, 594, 190, 740, 64, 819, 280, 216, 330, 989, 54, 1274, 504, 22, 1595, 256, 1710, 640, 714, 270, 2079, 874, 2345, 648, 56, 2484, 90, 2925, 1144, 286, 3239, 1450, 3740, 1560, 216, 832, 4464, 1914, 4850, 280, 320, 5049 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

This is the area of the triangle with vertices (1,p), (p,q), (q,pq).

A200050 gives the record values. [Arkadiusz Wesolowski, Apr 18 2012]

LINKS

Table of n, a(n) for n=1..61.

EXAMPLE

For p*q=3*5=15, |(3^2 + 5^2 - 5*(3^2 +1))/2| = 8

CROSSREFS

Sequence in context: A092971 A274195 A021975 * A021081 A018799 A076219

Adjacent sequences:  A192596 A192597 A192598 * A192600 A192601 A192602

KEYWORD

nonn

AUTHOR

J. M. Bergot, Jul 04 2011

EXTENSIONS

Definition simplified by N. J. A. Sloane, Jul 10 2011.

STATUS

approved

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Last modified February 17 18:46 EST 2019. Contains 320222 sequences. (Running on oeis4.)