A354074 Factorials that are the sum of the divisors of some m.

1, 6, 24, 120, 720, 5040, 40320, 362880, 3628800, 39916800, 479001600, 6227020800, 87178291200, 1307674368000, 20922789888000, 355687428096000, 6402373705728000, 121645100408832000, 2432902008176640000, 51090942171709440000, 1124000727777607680000

Offset

1,2

Comments

Sequence of different values of A000203(A245015(n)).

Conjecture: number 2 is the only factorial that is not in this sequence.

Links

Table of n, a(n) for n=1..21.

Example

Number 24 is in the sequence because sigma(14) = sigma(15) = sigma(23) = 24.

Crossrefs

Intersection of A000142 and A002191.

Cf. A000203, A338112, A055486, A055488, A245015, A354072, A354073, A338112.

Sequence in context: A324064 A050212 A369833 * A293300 A293487 A047865

Adjacent sequences: A354071 A354072 A354073 * A354075 A354076 A354077

Keyword

nonn

Author

Jaroslav Krizek, May 16 2022

Extensions

More terms from Jinyuan Wang, May 17 2022

Status

approved