2121728

Appears in sequences

• Number of set partitions of [n] such that the difference between each element and its index (in the partition) is a multiple of eight.at n=22A274865
• Numbers k with canonical prime factorization k = p1^e1*p2^e2*p3^e3 such that the points (p1, e1), (p2, e2) and (p3, e3) form a nondegenerate integer-sided triangle.at n=2A387586