214376

Appears in sequences

• 6*a(n) is the gap between sexy prime triples in the n-th sexy prime triple triple whose initial term is 5.at n=19A090775
• a(1) = greatest k such that H(k) - H(2) < 1/1 + 1/2; a(2) = greatest k such that H(k) - H(a(1)) < H(a(1)) - H(2); and for n>2, a(n) = greatest k such that H(k) - H(a(n-1)) < H(a(n-1)) - H(a(n-2)), where H = harmonic number.at n=7A227728
• Number of self-inverse permutations p on [n] where the maximal displacement of an element equals 3.at n=17A238914