

A083403


Write the numbers 1, 2, ... in a triangle with n terms in the nth row; a(n) = number of squarefree integers in nth row.


1



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, 19, 19, 18, 20, 19, 21, 21, 22, 24, 21, 24, 26, 22, 27, 26, 26, 27, 27, 29, 30, 30, 31, 32, 32, 33, 32, 34, 35, 35, 33, 36, 34, 36, 37, 40, 37, 42, 40, 41, 43, 42, 44, 40, 45, 44, 46
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OFFSET

1,2


LINKS

Table of n, a(n) for n=1..74.


EXAMPLE

Triangle begins
1 (1 squarefree)
2 3 (2 squarefree)
4 5 6 (2 squarefree)
7 8 9 10 (2 squarefree)
11 12 13 14 15 (4 squarefree)
16 17 18 19 20 21 (3 squarefree)


PROG

(PARI) {ts(m)=local(r, t); r=1; for(n=1, m, t=0; for(k=r, n+r1, if(issquarefree(k), t++)); print1(t", "); r=n+r; ) }


CROSSREFS

Cf. A066888, A005117.
Sequence in context: A257126 A050493 A085454 * A114091 A209580 A166008
Adjacent sequences: A083400 A083401 A083402 * A083404 A083405 A083406


KEYWORD

easy,nonn


AUTHOR

Jason Earls, Jun 07 2003


STATUS

approved



