27421

Appears in sequences

• Places k where A064608(k) (partial sums of unitary tau) is divisible by k.at n=5A064610
• Number of noncongruent integer-sided tetrahedra with largest side n.at n=15A097125
• Number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w^2<=x^2+y^2.at n=36A211806
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 221", based on the 5-celled von Neumann neighborhood.at n=34A270936
• Records in A095258.at n=16A350741
• Number of noncrossing partitions of the n-set including a part containing both 1 and n (with n different from 1), with no pair of singletons {i} and {j} that can be merged into {i,j} and leave the partition a noncrossing partition.at n=12A373760