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A162884 Half the difference between the larger and smaller term of the n-th amicable pair. 3
32, 13, 152, 272, 68, 56, 1155, 560, 6532, 32, 2025, 9009, 4490, 11835, 8775, 392, 5756, 13210, 2240, 2288, 9032, 2860, 42272, 40652, 55426, 21592, 8944, 8575, 5840, 1755, 34648, 38072, 33536, 38296, 4664, 57796, 35296, 30555, 10856, 41384, 88965, 22496 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..42.

FORMULA

a(n) = A066539(n)/2.

a(n) = (A259180(2n) - A259180(2n-1))/2. - Omar E. Pol, Oct 26 2017

EXAMPLE

a(7)=1155 because the 7th pair of amicable numbers is 12285 and 14595; and (14595-12285)/2=1155.

MAPLE

read("transforms3") ; L002046 := BFILETOLIST("b002046.txt") : L002025 := BFILETOLIST("b002025.txt") : A066539 := proc(n) global L002046, L002025; op(n, L002046)-op(n, L002025) ; end:

A162884 := proc(n) A066539(n)/2 ; end: seq(A162884(n), n=1..100) ; # R. J. Mathar, Jul 19 2009

MATHEMATICA

With[{s = PositionIndex@ Array[DivisorSigma[1, #] &, 10^6]}, Flatten@ Map[Differences, Apply[Join, Map[Function[n, Select[Subsets[Lookup[s, n], {2}], Total@ # == n &]], Sort@ Select[Keys@ s, Length@ Lookup[s, #] > 1 &]]]]/2] (* Michael De Vlieger, Oct 26 2017 *)

CROSSREFS

Cf. A063990, A066539, A259180.

Sequence in context: A305584 A316691 A275470 * A029771 A302684 A302519

Adjacent sequences:  A162881 A162882 A162883 * A162885 A162886 A162887

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Jul 16 2009

EXTENSIONS

Terms resorted along with A066539 by R. J. Mathar, Jul 19 2009

STATUS

approved

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Last modified October 28 10:01 EDT 2021. Contains 348327 sequences. (Running on oeis4.)