What are triangular-numbers?

Answer 1

Triangular numbers are numbers in the sequence 1, 1+2, 1+2+3, 1+2+3+4. This sequence can be represented by triangles as follows: (very crude figure with an even cruder browser!)x

x

xx

x

xx

xxx

x

xx

xxx

xxxx

and so on.

The nth term of this sequence is n*(n+1)/2.

Triangular numbers are numbers in the sequence 1, 1+2, 1+2+3, 1+2+3+4. This sequence can be represented by triangles as follows: (very crude figure with an even cruder browser!)x

x

xx

x

xx

xxx

x

xx

xxx

xxxx

and so on.

The nth term of this sequence is n*(n+1)/2.

Answer 2

Triangular numbers are numbers in the sequence 1, 1+2, 1+2+3, 1+2+3+4. This sequence can be represented by triangles as follows: (very crude figure with an even cruder browser!)x

x

xx

x

xx

xxx

x

xx

xxx

xxxx

and so on.

The nth term of this sequence is n*(n+1)/2.

Answer 3

Triangular numbers are numbers in the sequence 1, 1+2, 1+2+3, 1+2+3+4. This sequence can be represented by triangles as follows: (very crude figure with an even cruder browser!)x

x

xx

x

xx

xxx

x

xx

xxx

xxxx

and so on.

The nth term of this sequence is n*(n+1)/2.