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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
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.
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
KEYWORD
nonn
AUTHOR
Roger L. Bagula, May 29 2010
EXTENSIONS
Formula clarified by the Assoc. Eds. of the OEIS - Jun 07 2010
STATUS
approved