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A037984
Maximum number of trapezoids that can be formed by n lines in plane.
0
1, 5, 15, 31, 60, 108, 171, 264, 396, 556, 770, 1050, 1375, 1785, 2295, 2880, 3600, 4425, 5395
OFFSET
4,2
CROSSREFS
Sequence in context: A056108 A055831 A346823 * A298032 A073361 A155013
KEYWORD
nonn
STATUS
approved