What is Tetrahedral Number?
1.
The {n}th tetrahedral number is the sum of the first n Triangular numbers. Triangular numbers are the sum of the first n integers (1, 3, 6, 10, 15, etc.), and taking the sum of the triangular numbers results in the tetrahedral numbers (1, 4, 10, 20, 35, etc.)
The fifth tetrahedral number is the sum of the first five triangular numbers. The first five triangular numbers are 1, 3=1+2, 6=1+2+3, 10=1+2+3+4, and 15=1+2+3+4+5, so the sum of these numbers is 1+3+6+10+15= 35.
See
Random Words:
1.
Verb; To cheerfully and sincerely agree to do something; and then forget about it the moment the requester leaves and go back to surfing..
1.
Someone who retells the life of a deceased person. A Speaker for the Dead tells the story in all truth, holding back neither good nor ba..
