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%I #9 Apr 16 2014 05:42:48
%S 179210312,10189653632,11306629375,12372501247,12450928125,
%T 16064890623,100911346046,102029981184,103029727742,103538511872,
%U 103852693375,105264783872,107943730622,112167589373,114281242494,115827546751
%N First number in a sequence of 4 consecutive economical numbers.
%H J.-M. De Koninck and F. Luca, <a href="http://www.emis.de/journals/INTEGERS/papers/a5int2003/a5int2003.pdf">On strings of consecutive economical numbers of arbitrary length</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/EconomicalNumber.html">Economical Number</a>
%e a(2) = 10189653632 because 10189653632 ( = 2^7 * 79606669), 10189653633 ( = 3^6 * 733 * 19069), 10189653634 ( = 2 * 227^2 * 98873), 10189653635 ( = 5 * 7^3 * 5941489) form a sequence of 4 consecutive economical numbers.
%Y Cf. A047738.
%K hard,nonn,base
%O 1,1
%A Sudipta Das (juitech(AT)vsnl.net), Feb 12 2003
%E a(7)-a(16) from _Donovan Johnson_, Apr 14 2010
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