[Perfect number][1] is a positive integer that is equal to the sum of its proper divisors. The smallest perfect number is 6, which is the sum of 1, 2, and 3.

Is there a sequence of numbers which are equal to the sum of its proper divisors excluding itself as well as 1?

If yes, what are they called? Name first few numbers in the sequence.

Is there a general formula for them?

Please provide with some link to read more. [1]: https://www.britannica.com/topic/perfect-number

Perfect number is a positive integer that is equal to the sum of its proper divisors. The smallest perfect number is 6, which is the sum of 1, 2, and 3.

Is there a sequence of numbers which are equal to the sum of its proper divisors excluding itself as well as 1?

If yes, what are they called? Name first few numbers in the sequence.

Is there a general formula for them?

Please provide with some link to read more.