%I A083540
%S A083540 14,30,51,161,186,206,223,329,552,713,759,869,957,994,995,1248,1334,
%T A083540 1364,1634,1715,1819,2093,2133,2584,2685,2820,2821,2974,3115,3145,3485,
%U A083540 4212,4308,4312,4364,4408,4649
%N A083540 A083539[n] is a square; solutions x to sigma[x+1].sigma[x]=y^2 for some 
               y.
%e A083540 x=30: sigma[30]=72, sigma[31]=32,product=72.32=256.9=24^2
%t A083540 Do[s=Sqrt[DivisorSigma[1, n+1]*DivisorSigma[1, n]]; If[IntegerQ[s], Print[n]], 
               {n, 1, 5000}]
%Y A083540 Cf. A000203, A083539, A060780, A060781, A083538.
%Y A083540 Sequence in context: A044456 A132759 A011257 this_sequence A027575 A104776 
               A101960
%Y A083540 Adjacent sequences: A083537 A083538 A083539 this_sequence A083541 A083542 
               A083543
%K A083540 nonn
%O A083540 1,1
%A A083540 Labos E. (labos(AT)ana.sote.hu), May 21 2003