Similar to 三角数

Primorial

Prime power

Refactorable number

Taxicab number

Powerful number

Singly and doubly even

Centered nonagonal number

Centered pentagonal number

Centered triangular number

Centered square number

Centered tetrahedral number

Centered polygonal number

Centered heptagonal number

Centered octagonal number

Centered octahedral number

Centered hexagonal number

Central binomial coefficient

Centered cube number

Superabundant number

Superperfect number

Harmonic divisor number

Dedekind number

Lazy caterer's sequence

Narcissistic number

Binomial coefficient

Double factorial