cp's OEIS Frontend

A085578 Array read by antidiagonals: T(m,n) is the number of distinct products ij with 1<=i<=m, i<=j<=n, for m>=1, n>=1.

%I A085578 #4 Mar 30 2012 17:37:18
%S A085578 1,2,2,3,3,3,4,5,5,4,5,6,6,6,5,6,8,8,8,8,6,7,9,11,9,11,9,7,8,11,12,13,
%T A085578 13,12,11,8,9,12,15,15,14,15,15,12,9,10,14,17,19,17,17,19,17,14,10,11,
%U A085578 15,18,20,22,18,22,20,18,15,11,12,17,20,22,24,24,24,24,22,20,17,12,13,18,23,24,27,27,25,27,27,24,23,18,13
%N A085578 Array read by antidiagonals: T(m,n) is the number of distinct products ij with 1<=i<=m, i<=j<=n, for m>=1, n>=1.
%e A085578 Array begins:
%e A085578 1 2 3 4 5 6 7 8 9 10 ...
%e A085578 2 3 5 6 8 9 11 12 14 15 ...
%e A085578 3 5 6 8 11 12 15 17 18 20 ...
%e A085578 4 6 8 9 13 15 19 20 22 24 ...
%e A085578 5 8 11 13 14 17 22 24 27 28 ...
%p A085578 T := (m,n) -> nops({seq(seq(i*j, i=1..m),j=1..n)});
%t A085578 T[m_, n_] := Length[Union @@ Table[i*j, {i, m}, {j, n}]]
%Y A085578 A027424 is the main diagonal.
%K A085578 nonn,tabl
%O A085578 1,2
%A A085578 _Michael Kleber_, Jul 09 2003