A351623 Numbers k where 3k sets a record for the number of divisors of multiples of 3.

1, 2, 4, 8, 12, 16, 20, 40, 60, 80, 120, 240, 280, 420, 560, 840, 1680, 2520, 3360, 5040, 6720, 8400, 9240, 15120, 16800, 18480, 27720, 36960, 55440, 73920, 92400, 110880, 166320, 184800, 221760, 240240, 360360, 480480, 720720, 960960, 1201200, 1441440, 2162160, 2402400

Offset

1,2

Comments

This sequence may be useful for understanding A352797.

Links

Table of n, a(n) for n=1..44.

Formula

For n > 1, a(n) = A002182(n+2)/3.

Example

6 is not in the sequence because 3*6=18 and 3*4=12 each have 6 divisors.
8 is in the sequence because 3*8=24 sets a record for the number of divisors of multiples of 3.

Prog

(PARI) lista(nn) = {my(m=0, nm); for (n=1, nn, if ((nm=numdiv(3*n)) > m, m = nm; print1(n, ", ")); ); } \\ Michel Marcus, May 04 2022

Crossrefs

Cf. A002182, A352797.

Sequence in context: A118030 A187208 A349725 * A256409 A256403 A308013

Adjacent sequences: A351620 A351621 A351622 * A351624 A351625 A351626

Keyword

nonn

Author

J. Lowell, May 04 2022

Extensions

More terms from Michel Marcus, May 04 2022

Status

approved