A234471 Number of sets of 4 distinct collinear points in an n X n permutation array in which leftmost pair has same spacing as rightmost pair.
0, 0, 0, 2, 10, 30, 86, 180, 344, 624, 1056, 1626, 2522, 3646, 5118, 7164, 9784, 12868, 16848, 21438, 27202, 34298, 42550, 51800, 63184, 76256, 91032, 108086, 127850, 149442, 174902, 202552, 233608, 268512, 306664, 349394, 398226, 450510, 507038, 569204
Offset: 1
Keywords
Links
- Chris Swanson, Randy Ho, Bill Correll, Jr, Table of n, a(n) for n = 1..1000
Crossrefs
Cf. A243643.
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