This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A050340 Number of ways of factoring n with 3 levels of parentheses. 5
 1, 1, 1, 5, 1, 5, 1, 15, 5, 5, 1, 25, 1, 5, 5, 55, 1, 25, 1, 25, 5, 5, 1, 105, 5, 5, 15, 25, 1, 35, 1, 170, 5, 5, 5, 145, 1, 5, 5, 105, 1, 35, 1, 25, 25, 5, 1, 425, 5, 25, 5, 25, 1, 105, 5, 105, 5, 5, 1, 205, 1, 5, 25, 571, 5, 35, 1, 25, 5, 35, 1, 660, 1, 5, 25, 25, 5, 35, 1, 425, 55, 5 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS a(n) depends only on prime signature of n (cf. A025487). So a(24) = a(375) since 24=2^3*3 and 375=3*5^3 both have prime signature (3,1). LINKS R. J. Mathar, Table of n, a(n) for n = 1..1295 FORMULA Dirichlet g.f.: prod{n=2 to inf}(1/(1-1/n^s)^A050338(n)). a(n) = A050341(A101296(n)). - R. J. Mathar, May 26 2017 EXAMPLE 4=(((4)))=(((2*2)))=(((2)*(2)))=(((2))*((2)))=(((2)))*(((2))). CROSSREFS Cf. A001055, A050336-A050341. a(p^k)=A007714. a(A002110)=A000357. Sequence in context: A318664 A329031 A264483 * A021955 A055191 A299628 Adjacent sequences:  A050337 A050338 A050339 * A050341 A050342 A050343 KEYWORD nonn AUTHOR Christian G. Bower, Oct 15 1999. STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 10 04:15 EST 2019. Contains 329885 sequences. (Running on oeis4.)