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%I #6 Dec 15 2017 17:36:19
%S 1,2,2,2,4,3,3,6,6,5,7,8,8,8,10,8,10,11,12,13,15,11,14,14,16,14,15,19,
%T 19,19,18,20,19,21,21,22,24,21,24,26,22,27,26,26,27,27,29,30,30,31,32,
%U 32,33,32,34,35,35,33,36,34,36,37,40,37,42,40,41,43,42,44,40,45,44,46
%N Write the numbers 1, 2, ... in a triangle with n terms in the n-th row; a(n) = number of squarefree integers in n-th row.
%e Triangle begins
%e 1 (1 squarefree)
%e 2 3 (2 squarefree)
%e 4 5 6 (2 squarefree)
%e 7 8 9 10 (2 squarefree)
%e 11 12 13 14 15 (4 squarefree)
%e 16 17 18 19 20 21 (3 squarefree)
%o (PARI) {ts(m)=local(r, t); r=1; for(n=1,m,t=0; for(k=r,n+r-1,if(issquarefree(k),t++)); print1(t","); r=n+r;) }
%Y Cf. A066888, A005117.
%K easy,nonn
%O 1,2
%A _Jason Earls_, Jun 07 2003