A085089 Number of distinct prime signatures arising up to n.

1, 2, 2, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 9, 9, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 15, 15, 15

Offset: 1

Author

Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jul 02 2003

Keywords

• easy
• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..65536

Crossrefs

Cf. A025487.

Cf. A025488(n) = a(2^n); A124832 (table of the distinct prime signatures in the order they occur).

Programs

PARI

A085089(n)=#Set(apply(t->vecsort(factor(t)[,2]), [1..n])) \\ Not very efficient for large n > 10^5, but very quick up to the point where stack overflow occurs. - M. F. Hasler, Jul 16 2019

Extensions

More terms from Ray Chandler, Aug 17 2003