A355649 a(1) = a(2) = 1; for n > 2, a(n) is the smallest positive number that has the same number of divisors as the sum a(n-2) + a(n-1).

1, 1, 2, 2, 4, 6, 6, 12, 12, 24, 36, 60, 60, 120, 180, 180, 360, 360, 720, 840, 840, 1680, 2520, 2520, 5040, 7560, 10080, 10080, 20160, 27720, 27720, 55440, 83160, 110880, 110880, 221760, 332640, 554400, 554400, 1108800, 1441440, 1441440, 2882880, 4324320, 7207200, 7207200, 14414400, 21621600

Offset

1,3

Links

Table of n, a(n) for n=1..48.

Example

a(7) = 6 as a(5) + a(6) = 4 + 6 = 10 which has four divisors, and 6 is the smallest positive number that has four divisors.

Crossrefs

Cf. A355636, A000005, A351001, A352768, A352867, A352774.

Sequence in context: A000784 A355573 A092991 * A102425 A162608 A143216

Adjacent sequences: A355646 A355647 A355648 * A355650 A355651 A355652

Keyword

nonn

Author

Scott R. Shannon, Jul 12 2022

Status

approved