# explicit formula

Printable View

• Nov 18th 2008, 07:07 PM
dipstik05
explicit formula
what is the explicit formula for the sequence 2, 7, 15, 26, 40...

those are the first 5 #'s for a word problem about a card house and how many total cards are in the card house after each layer is added.

i've been thinking about it for awhile and i cant get it... somone please help quick :|
• Nov 18th 2008, 08:21 PM
Rapha
Quote:

Originally Posted by dipstik05
what is the explicit formula for the sequence 2, 7, 15, 26, 40...

those are the first 5 #'s for a word problem about a card house and how many total cards are in the card house after each layer is added.

i've been thinking about it for awhile and i cant get it... somone please help quick :|

2 + 5 = 7

7 + 8 = 15

15 + 11 = 26

26 + 14 = 40

40 + 17 = ...
• Nov 19th 2008, 12:23 PM
dipstik05
Quote:

Originally Posted by Rapha
2 + 5 = 7

7 + 8 = 15

15 + 11 = 26

26 + 14 = 40

40 + 17 = ...

that much i already knew, i can't write a forula for it