|
%I #11 Oct 02 2013 16:23:31
%S 4,50,134850,116026275,138982583000,1348770149848002
%N Smooth Power Trios: a(n) is the largest of three successive numbers a(n)-j, j=0..2, such that the largest prime factor of a(n)-j is <= the n-th root of a(n)-j.
%C The fifth term was found by R. Gerbicz, the others were found by F. Schneider.
%H Fred Schneider and R. Gerbicz, <a href="http://www.mersenneforum.org/showthread.php?t=5647">Smooth Power Trios</a>.
%e Example for n=6:
%e 1348770149848002 = 2 x 3 x 7 x 23 x 41 x 61^2 x 149 x 239 x 257,
%e 1348770149848001 = 19^3 x 89 x 103 x 229 x 283 x 331,
%e 1348770149848000 = 2^6 x 5^3 x 11 x 29 x 109 x 151 x 163 x 197,
%e This satisfies because 331 <= floor(1348770149848000^(1/6)) = 332.
%Y Cf. A122463, A122465.
%K hard,more,nonn
%O 1,1
%A _Fred Schneider_, Sep 09 2006
| 