login
Earliest sequence of 4 consecutive economical numbers.
1

%I #16 Feb 11 2018 04:09:21

%S 179210312,179210313,179210314,179210315

%N Earliest sequence of 4 consecutive economical numbers.

%H Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/NonRecursions.html">Non Recursions</a>

%H J.-M. De Koninck and F. Luca, <a href="https://www.emis.de/journals/INTEGERS/papers/a5int2003/a5int2003.Abstract.html">On strings of consecutive economical numbers of arbitrary length</a>, Integers: Electronic Journal of Combinatorial Number Theory 5, (2005), #A5.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/EconomicalNumber.html">Economical Number</a>

%e 179210312 = 2^3* 4733^2; 9 digits in 179219312, 7 digits in its prime factorization, 7 < 9, so that number is economical.

%Y Cf. A046759.

%K fini,full,nonn,base

%O 1,1

%A _Carlos Rivera_