The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A318796 Number of 2n-length words w over an n-ary alphabet {a1, a2, ..., an} such that #(w,a1) >= #(w,a2) >= ... >= #(w,an) >= 1, where #(w,x) counts the letters x in word w. 2
 1, 1, 10, 180, 6496, 322560, 25098480, 2437475040, 322951749120, 51882551360640, 10494386800934400, 2503138912988313600, 720738068391525381120, 239324670990042333696000, 92995858936970165240064000, 41062460981196018797072640000, 20742554869763399771711348736000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Alois P. Heinz, Table of n, a(n) for n = 0..238 FORMULA a(n) = A226874(2n,n). EXAMPLE a(2) = 10: aaab, aaba, aabb, abaa, abab, abba, baaa, baab, baba, bbaa. MAPLE b:= proc(n, i, t) option remember;       `if`(t=1, 1/n!, add(b(n-j, j, t-1)/j!, j=i..n/t))     end: a:= n-> `if`(n=0, 1, (2*n)!*b(2*n, 1, n)): seq(a(n), n=0..20); CROSSREFS Cf. A226874. Sequence in context: A001762 A034908 A030048 * A054918 A095807 A064092 Adjacent sequences:  A318793 A318794 A318795 * A318797 A318798 A318799 KEYWORD nonn AUTHOR Alois P. Heinz, Sep 03 2018 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 May 27 16:47 EDT 2020. Contains 334664 sequences. (Running on oeis4.)