28137

Appears in sequences

• Number of 5-bead necklaces labeled with numbers -n..n not allowing reversal, with sum zero and first differences in -n..n.at n=15A208996
• Fundamental discriminants d uniquely characterizing all complex biquadratic fields Q(sqrt(-3),sqrt(d)) which have 3-class group of type (3,3) and second 3-class group isomorphic to SmallGroup(729,34).at n=14A250241
• a(n) = 4*a(n-1) + a(n-2) - n for n > 1, with a(0) = 0, a(1) = 1.at n=9A271388
• Number of columns of length 1 in all bargraphs of semiperimeter n (n>=2).at n=10A273900
• T(n,k) is the number of permutations of [n] having exactly k pairs of integers i<j in [n] such that their cycle minima have opposite sorting order; triangle T(n,k), n>=0, 0<=k<=A125811(n)-1, read by rows.at n=55A381529