420000

Appears in sequences

• a(n) = Product_{k=1..n} s(n,k), where s(n,k) is unsigned Stirling number of the first kind. (s(n,k) = number of permutations of n elements which contain exactly k cycles.)at n=4A058807
• Number of nonoverlapping placements of one 1 X 1 square and one 2 X 2 square on an n X n board.at n=25A173963
• a(n) = 1*4*7 + 4*7*10 + 7*10*13 + ... (n terms).at n=15A196513
• Łukasiewicz words (without the last zero) for rooted plane trees where non-leaf branching can occur only at the leftmost branch of any level, but nowhere else.at n=34A209644
• Triangle S(n,k) by rows: coefficients of 5^((n-1)/2)*(x^(1/5)*d/dx)^n when n is odd, and of 5^(n/2)*(x^(4/5)*d/dx)^n when n is even.at n=32A223171
• Triangle S(n,k) by rows: coefficients of 5^(n/2)*(x^(4/5)*d/dx)^n when n=0,2,4,6,...at n=18A223530
• Integer areas of the tangential triangles corresponding to the integer-sided triangles with integer areas.at n=11A230361
• Integer areas A of integer-sided cyclic quadrilaterals such that the length of the circumradius is a perfect square.at n=22A233315
• Product of means of integer partitions with Heinz numbers from 2 to n.at n=16A327485
• Numbers k with squarefree kernel 210 such that both k-1 and k+1 are prime.at n=27A392030