654545

Appears in sequences

• G.f. := (1-sqrt(1-4*x+4*x^2-4*x^3))/(2(1-x+x^2)x).at n=16A152171
• Numbers in A245385 where P, Q, R, and S are all distinct.at n=29A245386
• Squarefree composite numbers n such that n*sigma(n) is of the form k*(k+1).at n=10A291192