%I A115157
%S A115157 480,504,560,576,630,672,720,792,840,960,1320,1350,1440,1512,1530,1680,
%T A115157 1950,2450,2520,4290
%N A115157 Numbers abc such that (a+2)(b+2)(c+2)=2abc.
%C A115157 There are 20 rectangular parallelepipeds with integer edges such that 
               increasing each edge by 2 doubles the volume, sorted in increasing 
               volume: {6,8,10}, {6,7,12}, {5,8,14}, {6,6,16}, {5,7,18}, {4,12,14}, 
               {4,10,18}, {4,9,22}, {5,6,28}, {4,8,30}, {3,20,22}, {3,18,25}, {3,
               16,30}, {4,7,54}, {3,15,34}, {3,14,40}, {3,13,50}, {5,5,98}, {3,12,
               70}, {3,11,130}
%e A115157 The third smallest product of abc such that (a+2)(b+2)(c+2)=2abc is 560, 
               so a(3)=560.
%Y A115157 Sequence in context: A056987 A025025 A108256 this_sequence A019287 A108876 
               A083728
%Y A115157 Adjacent sequences: A115154 A115155 A115156 this_sequence A115158 A115159 
               A115160
%K A115157 fini,full,nonn
%O A115157 1,1
%A A115157 Graeme McRae (g_m(AT)mcraefamily.com), Jan 14 2006