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A083403 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. 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 (list; graph; refs; listen; history; text; internal format)
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+r-1, 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

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Last modified October 13 20:38 EDT 2019. Contains 327981 sequences. (Running on oeis4.)