Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #14 Jul 15 2021 21:26:42
%S 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,
%T 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,
%U 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2
%N a(n) is the length of the cycle of the purely periodic unitary sigma aliquot cycles listed in A336216.
%C 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.
%H Hartmut F. W. Hoft, <a href="/A336218/a336218_1.pdf">Plot of 25th through 52nd pure unitary sigma aliquot cycles</a>
%e The first cycle of size 14 = a(8) starts at position: 1 + (1+3+1+1+2+2+5) = 16 in A336216.
%Y Cf. A034448, A327157, A336216, A336219.
%K nonn
%O 1,2
%A _Hartmut F. W. Hoft_, Jul 12 2020