A325436 Numbers m such that m! / sigma(m) is not an integer.

2, 3, 4, 9, 16, 25, 64, 289, 729, 1681, 2401, 3481, 4096, 5041, 7921, 10201, 15625, 17161, 27889, 28561, 29929, 65536, 83521, 85849, 146689, 262144, 279841, 458329, 491401, 531441, 552049, 579121, 597529, 683929, 703921, 707281, 734449, 829921, 1190281

Offset

1,1

Comments

Numbers A053182(n)^2 are terms for n >= 1.

Complement of A325435.

Union of the number 3 and numbers m from A023194 (sigma(m) = prime).

Links

Table of n, a(n) for n=1..39.

Prog

(Magma) [n: n in [1..10000] | not IsIntegral(Factorial(n)/&+[d: d in Divisors(n)])]
(PARI) isok(n) = ((n! % sigma(n)) != 0); \\ Michel Marcus, Apr 26 2019

Crossrefs

Cf. A000142, A000203, A023194, A053182, A325435.

Sequence in context: A235401 A354268 A281882 * A346777 A338585 A145027

Adjacent sequences: A325433 A325434 A325435 * A325437 A325438 A325439

Keyword

nonn

Author

Jaroslav Krizek, Apr 26 2019

Status

approved