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%I #9 Jul 25 2017 02:41:49
%S 0,15,65,80,175,255,369,544,609,624,671,1105,1295,1695,1776,2145,2320,
%T 2385,2400,2465,3439,3471,4015,4095,4160,4641,5936,6095,6305,6545,
%U 6560,7599,7825,8080,9855,9919,9999,10545,12209,12240,13345,13920,14016
%N Differences of two coprime 4th powers.
%C Primitive elements of A147857: any element n of A147857 is of the form a(k)*m^4 for some positive integer m.
%t Join[{0},Rest[#[[2]]-#[[1]]&/@Select[Subsets[Range[0,20]^4,{2}], CoprimeQ@@#&] //Union]] (* _Harvey P. Dale_, Dec 08 2016 *)
%Y Cf. A147854, A147856, A147857.
%K nonn
%O 0,2
%A _Max Alekseyev_, Nov 15 2008