A354073 Multiply-perfect numbers that are the sum of the divisors of some number.

1, 6, 28, 120, 496, 672, 30240, 32760, 523776, 2178540, 23569920, 33550336, 45532800, 142990848, 459818240, 1379454720, 1476304896, 8589869056, 14182439040, 31998395520, 43861478400, 51001180160, 66433720320, 137438691328, 153003540480, 403031236608, 518666803200

Offset: 1

Author

Jaroslav Krizek, May 16 2022

Keywords

• nonn

Comments

Conjecture: 8128 is only multiply-perfect number that is not in this sequence.

The distinct values of A000203(A066961(n)).

Examples

			The multiply-perfect number 28 is in the sequence because 28 = sigma(12).
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..50

Crossrefs

Intersection of A007691 and A002191.

Cf. A000203, A066961, A354072, A354074.

Programs

Magma

Set(Sort([&+Divisors(m): m in [1..10^7] | IsIntegral(&+Divisors(&+Divisors(m)) / &+Divisors(m))]))

Extensions

a(18)-a(27) from Amiram Eldar, May 12 2024