17-12n 17-12(10)=-103
31
The next number in the sequence 5-7-13-31 is 69.
The number halfway between 7 and 31 is 19.
49
81 - 50 = 31 50 - 19 = 31
31
39
The next number in the sequence 5-7-13-31 is 69.
Oh, dude, the tenth perfect number is 8,589,869,056. It's like a perfect number, but, you know, the tenth one. So, if you're ever in a situation where you need to know the tenth perfect number, now you're prepared. You're welcome.
a
The next number is 46. The sequence adds an increasing multiple of 3. 1+3 = 4, 4+6=10, 10+9=19, 19+12=31, and 31+15 = 46. With 1 as the value for n=1, the value for the nth term is x = 1.5 n² - 1.5n + 1 e.g. the 6th term is 1.5 (6x6) - 1.5 (6) + 1 = 54 - 9 + 1 = 46
The number halfway between 7 and 31 is 19.
31
49
61
192
yes it is