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A054573 Lesser members of g-reduced amicable pairs a < b such that sigma(a) = sigma(b) = a + b + gcd(a,b). 1
140, 174, 270, 280, 360, 552, 1002, 1146, 852, 1180, 1316, 984, 1575, 924, 1170, 2024, 1400, 2016, 2280, 4278, 3500, 4648, 3384, 5775, 5778, 4512, 6402, 3360, 4968, 10712, 5640, 10840, 12488, 14384, 14442, 13984, 9108, 14718, 15136, 15980, 11484, 19684, 22088 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The terms are ordered according to the their larger counterparts (A054572). - Amiram Eldar, Jan 19 2019

LINKS

Table of n, a(n) for n=1..43.

EXAMPLE

140 is in the sequence since it is the lesser member of the pair (140, 182), and sigma(140) = sigma(182) = 336 = 140 + 182 + gcd(140, 182).

MATHEMATICA

seq={}; Do[s1 = DivisorSigma[1, n]; Do[s2 = DivisorSigma[1, m]; If[s2 == s1 && s2 == n + m + GCD[n, m], AppendTo[seq, m]], {m, 1, n-1}], {n, 1, 1000}]; seq (* Amiram Eldar, Jan 19 2019 *)

CROSSREFS

Cf. A000203, A002025, A005820 (perfect numbers analog), A054572.

Sequence in context: A308617 A224982 A256085 * A131492 A276026 A259718

Adjacent sequences:  A054570 A054571 A054572 * A054574 A054575 A054576

KEYWORD

nonn

AUTHOR

Yasutoshi Kohmoto

EXTENSIONS

Corrected and extended by R. J. Mathar, Oct 19 2006

Name corrected and data corrected and extended by Amiram Eldar, Jan 19 2019

STATUS

approved

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Last modified November 17 03:06 EST 2019. Contains 329216 sequences. (Running on oeis4.)