199669

Properties

Appears in sequences

• Number of 7Xn -1,1 arrays such that the sum over i=1..7,j=1..n of i*x(i,j) is zero and rows are nondecreasing (ways to put n thrusters pointing east or west at each of 7 positions 1..n distance from the hinge of a south-pointing gate without turning the gate).at n=9A225314
• Prime numbers p such that the set of composite numbers in the range [p+1, nextprime(p)-1] has more than one element and all the elements have the same number of divisors.at n=22A332740
• Prime numbersat n=17955