This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A178542 #2 Mar 30 2012 17:34:41
%S A178542 64,26,304,544,136,112,2310,1120,3908,103,1530,3666,1097,21780,784,
%T A178542 15660,646,15554,4416,4512,11356,988,28080,36858,24840,30810,17888,
%U A178542 17150,11680,3510,9536,11440,9328,1724,5184,13888,13140,61110,18504
%N A178542 Difference A063990(2n)-A063990(2n-1) between amicable numbers.
%C A178542 Note that these are not differences between two members of amicable pairs
%C A178542 (see A066539) because A063990 is sorted and may separate pairs of amicable numbers.
%t A178542 (*A063990 Amicable numbers.*);
%t A178542 s[n_] := DivisorSigma[1, n] - n;
%t A178542 AmicableNumberQ[n_] := If[Nest[s, n, 2] == n && ! s[n] == n, True, False];
%t A178542 a = Select[Range[10^6], AmicableNumberQ[ # ] &];
%t A178542 Table[a[[n + 1]] - a[[n]], {n, 1, Length[a], 2}]
%Y A178542 Cf. A063990.
%K A178542 nonn
%O A178542 1,1
%A A178542 _Roger L. Bagula_, May 29 2010
%E A178542 Formula clarified by the Assoc. Eds. of the OEIS - Jun 07 2010