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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A246231 Number of compositions of n into exactly four different parts with distinct multiplicities. 2

%I

%S 12600,78120,189000,549000,1389960,2858640,6471699,15289662,29639082,

%T 64025820,134997382,267550925,545274648,1161661901,2223888268,

%U 4552401195,9185643748,17829746962,35102264675,71613947350,135793314152,270167493481,534784841445

%N Number of compositions of n into exactly four different parts with distinct multiplicities.

%H Alois P. Heinz and Vaclav Kotesovec, <a href="/A246231/b246231.txt">Table of n, a(n) for n = 20..220</a> (first 120 terms from Alois P. Heinz)

%t b[n_, i_, s_List] := b[n, i, s] = If[n == 0, Total[s]!, If[i<1, 0, Expand[ Sum[ If[j>0 && MemberQ[s, j], 0, If[j == 0, 1, x]*b[n-i*j, i-1, If[j == 0, s, s ~Union~ {j}]]/j!], {j, 0, n/i}]]]]; a[n_] := Coefficient[b[n, n, {}], x, 4]; Table[a[n], {n, 20, 50}] (* _Jean-Fran├žois Alcover_, Feb 11 2015, after _Alois P. Heinz_ *)

%Y Column k=4 of A242896.

%K nonn

%O 20,1

%A _Alois P. Heinz_, Aug 19 2014

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 30 03:19 EDT 2020. Contains 337432 sequences. (Running on oeis4.)