0,6
n(n+1)(n-1)/24 when n is odd; n(n-2)(n-4)/24 when n is even
Union of A000330, A007290.
Sequence in context: A085436 A158868 A104634 this_sequence A128142 A111267 A146343
Adjacent sequences: A060419 A060420 A060421 this_sequence A060423 A060424 A060425
easy,nonn
Sen-Peng You (giawgwan(AT)single.url.com.tw), Apr 05 2001
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