169580

Appears in sequences

• a(1)=1. a(n) = Sum_{1<=k<n, gcd(k,n(n+1))=1} a(k).at n=50A125596
• Number of n X 2 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X 3 binary array having nonzero determinant, with rows and columns of the latter in lexicographically nondecreasing order.at n=22A227554
• Number of partitions of n into 10 parts such that every i-th smallest part (counted with multiplicity) is different from i.at n=27A244246