|
%I #22 Sep 14 2013 13:37:58
%S 1,4,2,3,5,6,7,8,9,14,16,18,19,22,23,24,25,26,27,28,29,32,33,34,35,36,
%T 37,38,39,41,42,43,44,45,46,47,48,49,52,53,54,55,56,57,58,59,61,62,63,
%U 64,65,66,67,68,69,72,73,74,75,76,77,78,79,81,82,83,84
%N Starting with 1, smallest integer not having a zero and not yet in the sequence such that two neighboring digits of the sequence multiply to a composite.
%C The number after 1 has to be 4, because the product 1*4 must be composite.
%C Then 2 is OK, because 4*2 = 8 is composite.
%C Then 3, because 2*3 = 6 is composite, and so on.
%C Note that 14 is the term after 9 because 10 is now the smallest candidate, but 10 has a 0 digit, 11 consists of two unit digits, and 12 and 13 have digit products 2 and 3, which are prime. - _T. D. Noe_, Apr 25 2012
%Y Cf. A182272.
%K nonn,base,easy,nice
%O 1,2
%A _Jim Nastos_ and _Eric Angelini_, Apr 22 2012
|
