150071

Appears in sequences

• Quasi-Carmichael numbers to base -9: squarefree composites n such that prime p|n ==> p+9|n+9.at n=10A029569
• Composite numbers k such that if k = a U b (where U denotes concatenation) then a' + b' = k', where a', b' and k' are the arithmetic derivatives of a, b and k.at n=21A239724
• Composite numbers k = concat(MSD(k),x) such that k' = x', where k' is the arithmetic derivative of k.at n=23A293477