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Aliquot sequence starting at 702.
2

%I #17 Oct 16 2023 16:13:51

%S 702,978,990,1818,2160,5280,12864,21680,28912,31848,47832,71808,

%T 148512,359520,946848,1895712,4539360,12180336,23781648,44267568,

%U 76111632,139130668,104348008,92030552,80526748,62286692,55099864,51042536,47249404,35492780,39042100

%N Aliquot sequence starting at 702.

%C This sequence is one of the first ones that contains numbers that exceed 2^64 and yet is known to terminate in a small prime followed by 1 and 0.

%C Note how all the numbers in the sequence are even, except the last 6 (not counting 0).

%D R. K. Guy, Unsolved Problems in Number Theory, B6.

%D Enoch Haga, Exploring Prime Numbers on Your PC, 2nd ed., 1998, pages 83-84 and Table 8, page 46. ISBN 1-885794-16-9.

%H Daniel Mondot, <a href="/A269542/b269542.txt">Table of n, a(n) for n = 0..301</a>

%F a(n+1) = A001065(a(n)). - _R. J. Mathar_, Oct 11 2017

%t NestWhileList[DivisorSigma[1,#]-#&,702,#>0&] (* _Paolo Xausa_, Oct 16 2023 *)

%o (PARI) lista() = {print1(a=702, ", "); until (!a, a = sigma(a) - a; print1(a, ", "););} \\ _Michel Marcus_, Feb 29 2016

%Y Cf. A001065, A008888.

%K nonn,fini,full

%O 0,1

%A _Daniel Mondot_, Feb 29 2016