201726

Appears in sequences

• Triangle read by rows, giving T(n,k) = number of k-member minimal ordered covers of a labeled n-set (1 <= k <= n).at n=23A049055
• Number of functions f:{1,2,...,n}->{1,2,...,n} such that Im(f) contains 3 fixed elements.at n=4A126779
• Number of binary strings of length n with equal numbers of 00010 and 11001 substrings.at n=19A164225
• Triangular array T(n,k): functions f:{1,2,...,n}-> {1,2,...,n} such that each of k fixed (but arbitrary) elements are in the image of f.at n=31A174551
• Third differences of seventh powers (A001015).at n=6A255181
• G.f. A(x,y) satisfies: A(x,y) = x * (1 + y*A(x,y)*A'(x,y)) / (1 + A(x,y)*A'(x,y)), where A'(x,y) = d/dx A(x,y).at n=23A301930
• Triangle read by rows: T(n,k) = Sum_{j=0..k} (-1)^(k-j) * binomial(k,j) * (4+j)^n.at n=31A391633