%I A057570
%S A057570 0,3,4,13,15,30,33,54,58,85,90,123,129,168,175,220,228,279,288,
%T A057570 345,355,418,429,498,510,585,598,679,693,780,795,888,904,1003,1020,
%U A057570 1125,1143,1254,1273,1390,1410,1533,1554,1683,1705,1840,1863,2004
%N A057570 Numbers of the form n*(7n+-1)/2.
%t A057570 lst={};s=0;Do[s+=n/7;If[Floor[s]==s,AppendTo[lst,s]],{n,0,7!}];lst [From 
               Vladimir Orlovsky (4vladimir(AT)gmail.com), Jan 06 2009]
%Y A057570 Cf. A074378, A001318, A057569, A154260, A154292, A154293 [From Vladimir 
               Orlovsky (4vladimir(AT)gmail.com), Jan 06 2009]
%Y A057570 Sequence in context: A053910 A105074 A087884 this_sequence A024853 A023857 
               A026700
%Y A057570 Adjacent sequences: A057567 A057568 A057569 this_sequence A057571 A057572 
               A057573
%K A057570 nonn
%O A057570 1,2
%A A057570 N. J. A. Sloane (njas(AT)research.att.com), Oct 04 2000