A309243 Completely multiplicative with a(p) = p * a(p-1) for any prime number p.

1, 2, 6, 4, 20, 12, 84, 8, 36, 40, 440, 24, 312, 168, 120, 16, 272, 72, 1368, 80, 504, 880, 20240, 48, 400, 624, 216, 336, 9744, 240, 7440, 32, 2640, 544, 1680, 144, 5328, 2736, 1872, 160, 6560, 1008, 43344, 1760, 720, 40480, 1902560, 96, 7056, 800, 1632, 1248

Offset

1,2

Comments

All terms are distinct and belong to A064522.

Links

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Formula

a(n) >= n with equality iff n is a power of 2.

a(n) is a multiple of n.

a(n) is a multiple of A000010(n).

A006530(a(n)) = A006530(n).

A053585(a(n)) = A053585(n).

Apparently, A007814(a(n)) = A064415(n).

Example

a(2) = 2 * a(1) = 2.
a(5) = 5 * a(4) = 5 * a(2)^2 = 5 * 2^2 = 20.

Prog

(PARI) a(n) = my (f=factor(n), p=f[, 1]~, e=f[, 2]~); prod (i=1, #p, (p[i] * a(p[i] - 1))^e[i])

Crossrefs

Cf. A000010, A006530, A053585, A064415, A064522.

Sequence in context: A299822 A052100 A079579 * A112326 A075435 A069875

Adjacent sequences: A309240 A309241 A309242 * A309244 A309245 A309246

Keyword

nonn,mult

Author

Rémy Sigrist, Jul 17 2019

Status

approved