Friday

March 27, 2015

March 27, 2015

Posted by **number theory** on Wednesday, March 27, 2013 at 1:11am.

- maths -
**Reiny**, Wednesday, March 27, 2013 at 9:59amso we need to look at the number before a perfect square and see if it is a prime or not

4-1 = 3 , 1x3 , 1 is not considered prime

9-1 = 8 more than 1 pair of factors

16-1 = 15 --> 3x5 , both prime ✔

25-1 = 24 lots of pairs

36-1 = 35 --> 5x7 , both prime ✔

49-1 = 48 lots

64-1 = 63 lots

81 - 1 = 80 lots

100-1 = 99 lots

so the only n values are 4 and 6

and their sum is 10

**Answer this Question**

**Related Questions**

Maths - What is the sum of all integer values of n satisfying 1≤n≤...

Maths - What is the sum of all integer values of n satisfying 1≤n≤...

Maths - What is the sum of all integer values of n satisfying 1≤n≤...

MATHS!!!Please HELP..:'( - What is the sum of all integer values of n satisfying...

Algebra - What is the sum of all integer values of n satisfying 1 \leq n \leq ...

Maths - Suppose a and b are positive integers satisfying 1≤a≤31, 1&#...

Maths - Let f be a function such that f(−6)=−6, f(6)=6, f is ...

Math (algebra) - Suppose a and b are positive integers satisfying 1≤a&#...

algebra 1 help please - 4) a student score is 83 and 91 on her first two quizzes...

Calculus - Let f be a function such that f(−6)=−6, f(6)=6, f is ...