This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A126787 G.f.: B(x)*B(2!*x^2)*B(3!*x^3)*..., where B(x) is g.f. of A000142. 2
 1, 1, 4, 14, 66, 308, 1888, 12240, 95640, 827904, 8106960, 87387264, 1035645312, 13316300928, 184988692800, 2756878875648, 43888205438208, 742943286892800, 13326434312808960, 252448071959572992, 5036116692383428608, 105523926692032447488 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Take each Ferrers diagram of the partitions of n, label(linearly order) the dots within each row, then linearly order any of the rows that are of equal length. [From Geoffrey Critzer, Mar 21 2009] LINKS Alois P. Heinz, Table of n, a(n) for n = 0..175 MAPLE B:= proc(n) option remember; local x; unapply (`if`(n<=0, 1, B(n-1)(x)+ n! *x^n), x) end: BB:= proc(n) local x, d; unapply (convert (series (mul (B (floor (n/d))(d!*x^d), d=1..n), x, n+1), polynom), x) end: a:= n-> coeff (BB(n)(x), x, n): seq (a(n), n=0..25); # Alois P. Heinz, Sep 25 2008 MATHEMATICA CoefficientList[Series[Product[Sum[x^(n*k) n!^k*k!, {k, 0, 20}], {n, 1, 20}], {x, 0, 20}], x] [From Geoffrey Critzer, Mar 21 2009] CROSSREFS Cf. A096161, A110143. Sequence in context: A020041 A081891 A119857 * A187742 A129219 A007025 Adjacent sequences:  A126784 A126785 A126786 * A126788 A126789 A126790 KEYWORD easy,nonn AUTHOR Vladeta Jovovic, Feb 18 2007 EXTENSIONS More terms from Alois P. Heinz, Sep 25 2008 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .