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 A178542 Difference A063990(2n)-A063990(2n-1) between amicable numbers. 0
 64, 26, 304, 544, 136, 112, 2310, 1120, 3908, 103, 1530, 3666, 1097, 21780, 784, 15660, 646, 15554, 4416, 4512, 11356, 988, 28080, 36858, 24840, 30810, 17888, 17150, 11680, 3510, 9536, 11440, 9328, 1724, 5184, 13888, 13140, 61110, 18504 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Note that these are not differences between two members of amicable pairs (see A066539) because A063990 is sorted and may separate pairs of amicable numbers. LINKS Table of n, a(n) for n=1..39. MATHEMATICA (*A063990 Amicable numbers.*); s[n_] := DivisorSigma[1, n] - n; AmicableNumberQ[n_] := If[Nest[s, n, 2] == n && ! s[n] == n, True, False]; a = Select[Range[10^6], AmicableNumberQ[ # ] &]; Table[a[[n + 1]] - a[[n]], {n, 1, Length[a], 2}] CROSSREFS Cf. A063990. Sequence in context: A281721 A303319 A275469 * A066539 A095390 A033384 Adjacent sequences: A178539 A178540 A178541 * A178543 A178544 A178545 KEYWORD nonn AUTHOR Roger L. Bagula, May 29 2010 EXTENSIONS Formula clarified by the Assoc. Eds. of the OEIS - Jun 07 2010 STATUS approved

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Last modified December 9 03:46 EST 2023. Contains 367681 sequences. (Running on oeis4.)