A027422 Triangle T00, T10, T11, T20, T21, T22, etc. where Tmn = number of distinct products ij with m-n<=i,j<=m.

1, 1, 2, 1, 3, 4, 1, 3, 6, 7, 1, 3, 6, 9, 10, 1, 3, 6, 10, 14, 15, 1, 3, 6, 10, 14, 18, 19, 1, 3, 6, 10, 15, 20, 25, 26, 1, 3, 6, 10, 15, 20, 25, 30, 31, 1, 3, 6, 10, 15, 20, 26, 31, 36, 37, 1, 3, 6, 10, 15, 21, 26, 32, 37, 42, 43, 1, 3, 6, 10, 15, 21, 28, 34, 41, 47, 53, 54, 1, 3, 6

Offset: 0

Author

N. J. A. Sloane

Keywords

• tabl
• nonn
• easy

Examples

			1 ;
1 2 ;
1 3 4 ;
1 3 6 7 ;
1 3 6 9 10 ;
1 3 6 10 14 15 ;
1 3 6 10 14 18 19 ;
1 3 6 10 15 20 25 26 ;
1 3 6 10 15 20 25 30 31 ;
1 3 6 10 15 20 26 31 36 37 ;
1 3 6 10 15 21 26 32 37 42 43 ;
1 3 6 10 15 21 28 34 41 47 53 54 ;
1 3 6 10 15 21 27 34 40 47 53 59 60 ;
		

Links

• R. J. Mathar, Table of n, a(n) for n = 0..1890

Crossrefs

Cf. A027384, A027421.

Programs

Maple

A027422 := proc(m,n)
    local L,i,j ;
    L := {};
    for i from m-n to m do
        for j from i to m do
            L := L union {i*j};
        end do:
    end do:
    nops(L);
end proc: # R. J. Mathar, May 06 2016

Extensions

More terms from Olivier Gérard, Nov 15 1997