cp's OEIS Frontend

A261844 Number of compositions of n into distinct parts where each part i is marked with a word of length i over a senary alphabet whose letters appear in alphabetical order.

%I A261844 #4 Sep 03 2015 06:25:38
%S A261844 1,6,21,308,798,4116,51114,126288,502947,1912318,26074881,55301652,
%T A261844 210871038,643901916,2416831656,32128430000,64611765009,218800524222,
%U A261844 625968110257,1971079800312,6127902153366,88805517515284,163129580373222,530136843388056
%N A261844 Number of compositions of n into distinct parts where each part i is marked with a word of length i over a senary alphabet whose letters appear in alphabetical order.
%C A261844 Also matrices with six rows of nonnegative integers with distinct positive column sums and total element sum n.
%H A261844 Alois P. Heinz, <a href="/A261844/b261844.txt">Table of n, a(n) for n = 0..5000</a>
%p A261844 b:= proc(n, i, p) option remember;
%p A261844       `if`(i*(i+1)/2<n, 0, `if`(n=0, p!, b(n, i-1, p)+
%p A261844       `if`(i>n, 0, b(n-i, i-1, p+1)*binomial(i+5, 5))))
%p A261844     end:
%p A261844 a:= n-> b(n$2, 0):
%p A261844 seq(a(n), n=0..30);
%Y A261844 Column k=6 of A261835.
%K A261844 nonn
%O A261844 0,2
%A A261844 _Alois P. Heinz_, Sep 03 2015