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Number of composites that are a concatenation nk of n and k for values of k from 1 to n.
0

%I #5 Dec 15 2017 17:36:03

%S 0,2,2,2,4,5,5,7,8,6,10,11,10,13,12,13,15,16,14,18,18,17,20,20,22,22,

%T 22,25,26,26,26,29,26,30,28,31,32,33,32,34,35,35,37,39,40,39,42,44,42,

%U 44,48,46,49,44,50,48,49,49,53,52,52,56,53,57,57,60,60,60,61,61,65,63

%N Number of composites that are a concatenation nk of n and k for values of k from 1 to n.

%e a(4) = 2 because we get composites 42 and 44 for 2 values of k, i.e. k = 2, 4.

%Y Cf. A068696.

%K base,easy,nonn

%O 1,2

%A _Jason Earls_, Sep 06 2002