We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive pseudonymised information about your use of our website.
Please click on "Accept cookies" if you agree to the setting of cookies. Cookies that do not require consent remain unaffected by this, see
cookie policy and privacy policy.
DECLINE COOKIES

How many numbers are there between 1 and 10,000 that have "prime factors" strictly between 30 and 100 only? No prime factors below 30 and above 100 are allowed. Any help would be greatly appreciated. Thank you.

Guest Feb 28, 2019

#1**0 **

**(961, 1147, 1271, 1333, 1369, 1457, 1517, 1591, 1643, 1681, 1739, 1763, 1829, 1849, 1891, 1927, 1961, 2021, 2077, 2173, 2183, 2201, 2209, 2257, 2263, 2279, 2419, 2449, 2479, 2491, 2501, 2537, 2573, 2623, 2627, 2701, 2747, 2759, 2773, 2809, 2867, 2881, 2911, 2923, 2993, 3007, 3053, 3071, 3127, 3139, 3149, 3233, 3239, 3293, 3337, 3397, 3403, 3431, 3481, 3551, 3569, 3589, 3599, 3649, 3713, 3721, 3763, 3827, 3869, 3901, 3953, 3977, 4087, 4171, 4183, 4187, 4189, 4307, 4331, 4399, 4453, 4489, 4559, 4661, 4717, 4757, 4819, 4891, 4897, 5041, 5063, 5141, 5183, 5251, 5293, 5329, 5429, 5561, 5609, 5723, 5767, 5893, 5917, 5963, 6059, 6241, 6319, 6497, 6499, 6557, 6887, 6889, 7031, 7081, 7387, 7663, 7921, 8051, 8633, 9409) = 120 such numbers. ALL these numbers have Prime Factors that fall between 31 and 97. There are 15 Prime Numbers that form the basis of the 120 numbers above as follows: 31 , 37 , 41 , 43 , 47 , 53 , 59 , 61 , 67 , 71 , 73 , 79 , 83 , 89 , 97. And the above 120 numbers range between 31^2 and 97^2, and are calculated as follows: 15(nCr)2 =105 + 15 squares(31^2, 37^2, 41^2.....and **

Guest Feb 28, 2019