18974

Appears in sequences

• Column 5 of triangle A055907.at n=7A055911
• a(n) = (n!)^2 * Sum_{k=1..n} 1/(k^2*(k-1)!).at n=4A061572
• Consider recurrence b(0) = (2n+1)/2, b(n) = b(0)*ceiling(b(n-1)); sequence gives first integer reached.at n=25A081849
• sigma(n) + phi(n) is a fourth power.at n=8A114068
• Numbers n such that A193232(n) is a triangular number.at n=12A220518
• a(n) = PrimePi(A246033(n)) (where PrimePi = A000720).at n=44A290652