Math Is Fun Forum

mathxyz

Member

From: Brooklyn, NY

Registered: 2024-02-24

Posts: 1,053

Seeking Formula

What is the formula for determining the 7th number on the 20th row of the famous Pascal Triangle?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,591

Re: Seeking Formula

If 1 is the zero row and 1  1 the first row and 1  2  1 the second row then the formula is

where n is the row number and r the (r+1) th element.

So put n=20 and r = 6

Bob

If you ask me nicely on Wednesday I'll show you the proof (by induction).

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

mathxyz

Member

From: Brooklyn, NY

Registered: 2024-02-24

Posts: 1,053

Re: Seeking Formula

If 1 is the zero row and 1  1 the first row and 1  2  1 the second row then the formula is

where n is the row number and r the (r+1) th element.

So put n=20 and r = 6

Bob

If you ask me nicely on Wednesday I'll show you the proof (by induction).

Ok. Looks easy to do. Thanks.