%I A072890
%S A072890 14316,19116,31704,47616,83328,177792,295488,629072,589786,294896,
%T A072890 358336,418904,366556,274924,275444,243760,376736,381028,285778,152990,
%U A072890 122410,97946,48976,45946,22976,22744,19916,17716,14316
%N A072890 The 28-cycle of the n => sigma(n)-n process, where sigma(n) is the sum 
               of divisors of n (A000203).
%C A072890 Called a "sociable" chain.
%D A072890 P. Poulet, Parfaits, amiables et extensions, Editions Stevens, Bruxelles, 
               1918.
%F A072890 a(28+n)=a(n).
%t A072890 f[n_]:=Plus@@Divisors[n]-n;a=7524;Table[a=f[a],{n,0,28}] [From Vladimir 
               Orlovsky (4vladimir(AT)gmail.com), Nov 01 2009]
%Y A072890 Cf. A000203, A045477, A072891.
%Y A072890 Sequence in context: A115554 A106726 A064965 this_sequence A049442 A106725 
               A144649
%Y A072890 Adjacent sequences: A072887 A072888 A072889 this_sequence A072891 A072892 
               A072893
%K A072890 fini,full,nonn,new
%O A072890 1,1
%A A072890 Miklos Kristof (kristmikl(AT)freemail.hu), Jul 29 2002