A336218 a(n) is the length of the cycle of the purely periodic unitary sigma aliquot cycles listed in A336216.

1, 3, 1, 1, 2, 2, 5, 14, 2, 14, 2, 14, 2, 2, 2, 1, 2, 2, 2, 2, 4, 2, 2, 4, 2, 65, 2, 2, 2, 6, 25, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 39, 26, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2

Offset

1,2

Comments

For the definition of unitary divisors see A034448. This sequence has been calculated from the table of 440 lines in the link of A327157 of Antti Karttunen. That table contains the numbers in 122 complete cycles and in 5 incomplete 2-cycles with values larger than number 27287260 in line 440 which results in the cumulative sum of 445 for the data listed in this sequence.

Links

Table of n, a(n) for n=1..89.

Hartmut F. W. Hoft, Plot of 25th through 52nd pure unitary sigma aliquot cycles

Example

The first cycle of size 14 = a(8) starts at position: 1 + (1+3+1+1+2+2+5) = 16 in A336216.

Crossrefs

Cf. A034448, A327157, A336216, A336219.

Sequence in context: A364757 A204253 A064048 * A016464 A245570 A243925

Adjacent sequences: A336215 A336216 A336217 * A336219 A336220 A336221

Keyword

nonn

Author

Hartmut F. W. Hoft, Jul 12 2020

Status

approved