A064453 Number of finite positive integer sequences b(1),...,b(k), with k <= n and b(1)*b(2)*...*b(k) <= n.

1, 5, 15, 44, 85, 216, 343, 806, 1299, 2155, 2926, 7162, 9477, 13209, 17935, 37824, 47957, 75600, 93613, 138074, 170730, 209000, 249481, 635974, 764425, 915551, 1109772, 1390375, 1624029, 2103690, 2430431, 5120488, 5976553, 6946897

Offset

1,2

Comments

The subsequence of primes begins 5, then no more through a(34). What is the next prime? - Jonathan Vos Post, Jan 07 2011

Links

Charlie Neder, Table of n, a(n) for n = 1..1000

Example

Sequences b for n = 2 are {1}, {2}, {1, 1}, {2, 1}, {1, 2}, so a(2)=5.

Crossrefs

Sequence in context: A178965 A005665 A025471 * A059251 A295179 A274020

Adjacent sequences: A064450 A064451 A064452 * A064454 A064455 A064456

Keyword

nice,nonn

Author

Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Oct 02 2001

Extensions

a(21)-a(34) from Donovan Johnson, Sep 06 2010

Status

approved