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 A002046 Larger of amicable pair. (Formerly M5435 N2363) 75
 284, 1210, 2924, 5564, 6368, 10856, 14595, 18416, 76084, 66992, 71145, 87633, 88730, 124155, 139815, 123152, 153176, 168730, 176336, 180848, 203432, 202444, 365084, 389924, 430402, 399592, 455344, 486178, 514736, 525915, 669688, 686072 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The elements 76084, 123152, etc. are intentionally out of numerical order so that a(n) and A002025(n) form amicable pairs. - Michael B. Porter, Apr 17 2010 All terms are deficient (A005100). - Michel Marcus, Mar 10 2013 For the related amicable pairs see A259180. - Omar E. Pol, Jul 15 2015 REFERENCES N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). For additional references see A002025. LINKS T. D. Noe and Sergei Chernykh, Table of n, a(n) for n = 1..415523 [All terms such that the smaller number A002025(n) is < 10^17. Terms 39375 through 415523 were computed by Sergei Chernykh] J. Bell, A translation of Leonhard Euler's "On amicable numbers", arXiv:math/0409196 [math.HO], 2004-2009. S. Chernykh, Amicable pairs list E. B. Escott, Amicable numbers, Scripta Mathematica, 12 (1946), 61-72 [Annotated scanned copy] M. Garcia, A Million New Amicable Pairs, J. Integer Seqs., Vol. 4 (2001), #01.2.6. S. S. Gupta, Amicable Numbers Hisanori Mishima, First 236 amicable pairs D. Moews, Perfect, amicable and sociable numbers Passawan Noppakaew and Prapanpong Pongsriiam, Product of Some Polynomials and Arithmetic Functions, J. Int. Seq. (2023) Vol. 26, Art. 23.9.1. J. O. M. Pedersen, Known Amicable Pairs [Broken link] J. O. M. Pedersen, Tables of Aliquot Cycles [Broken link] J. O. M. Pedersen, Tables of Aliquot Cycles [Via Internet Archive Wayback-Machine] J. O. M. Pedersen, Tables of Aliquot Cycles [Cached copy, pdf file only] T. Trotter, Jr., Amicable Numbers [Warning: As of March 2018 this site appears to have been hacked. Proceed with great caution. The original content should be retrieved from the Wayback machine and added here. - N. J. A. Sloane, Mar 29 2018] Eric Weisstein's World of Mathematics, Amicable Pair FORMULA a(n) = A259180(2n) = A180164(n) - A259180(2n-1) = A180164(n) - A002025(n). - Omar E. Pol, Jul 15 2015 MAPLE f:= proc(t) uses numtheory; local s; s:= sigma(t) - t; s > t and sigma(s) - s = t end proc; Am1:= select(f, [\$1..10^6]); map(numtheory:-sigma, Am1); # Robert Israel, Jul 16 2015 MATHEMATICA amicableQ[n_] := With[{s = DivisorSigma[1, n] - n}, r = n != s && n == DivisorSigma[1, s] - s; If[r, mate[n] = s; True, False]]; mate /@ Select[ Range[lim], amicableQ[#] && # < mate[#] &] (* Jean-François Alcover, Sep 20 2011 *) Table[DivisorSigma[1, A002025[n]] - A002025[n], {n, 50}] (* T. D. Noe, Sep 20 2011 *) PROG (PARI) aliquot(n)=sigma(n)-n isA002046(n)={local(a); a=aliquot(n); a

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Last modified December 4 11:15 EST 2023. Contains 367560 sequences. (Running on oeis4.)