A074906 Aliquot sequence starting at 1521.

1521, 858, 1158, 1170, 2106, 2976, 5088, 8520, 17400, 38400, 88452, 196924, 228004, 255836, 255892, 339948, 708372, 1392748, 1392804, 2631580, 3684548, 3684604, 4502876, 4502932, 4630444, 5343604, 5343660, 13185396, 26489484

Offset

0,1

Comments

This aliquot sequence starts with the least odd number such that the sequence does not repeat a term after 20 or fewer terms.

References

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

Links

T. D. Noe, Table of n, a(n) for n = 0..169

Christophe CLAVIER, Aliquot Sequences

Formula

a(n+1) = A001065(a(n)). - R. J. Mathar, Oct 11 2017

Example

a(0)= 1521, a(1) = sigma(1521) - 1521 = 858.

Mathematica

FixedPointList[If[# > 0, DivisorSigma[1, #] - #, 0]&, 1521] // Most (* Jean-François Alcover, Mar 28 2020 *)

Crossrefs

Cf. A008888, A008889.

Sequence in context: A157375 A331659 A174746 * A307745 A025413 A025410

Adjacent sequences: A074903 A074904 A074905 * A074907 A074908 A074909

Keyword

nonn,fini,full

Author

Robert A. Stump (bee_ess107(AT)msn.com), Sep 30 2002

Status

approved