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A236627 Number of positive integers <= sqrt(n) not dividing n. 1
0, 0, 0, 0, 1, 0, 1, 0, 1, 1, 2, 0, 2, 1, 1, 1, 3, 1, 3, 1, 2, 2, 3, 0, 3, 3, 3, 2, 4, 1, 4, 2, 3, 3, 3, 1, 5, 4, 4, 2, 5, 2, 5, 3, 3, 4, 5, 1, 5, 4, 5, 4, 6, 3, 5, 3, 5, 5, 6, 1, 6, 5, 4, 4, 6, 4, 7, 5, 6, 4, 7, 2, 7, 6, 5, 5, 6, 4, 7, 3, 6, 7, 8, 3, 7, 7, 7, 5, 8, 3, 7, 6, 7, 7, 7, 3, 8, 6, 6, 5, 9 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,11

COMMENTS

It appears that the indices of the zeros in the sequence are in A018253.

LINKS

Table of n, a(n) for n=1..101.

Omar E. Pol, , Three illustrations of A000005 giving the structure of this sequence, (2013)

FORMULA

a(n) = A000196(n) - A038548(n) = A160812(n)/2.

PROG

(PARI) a(n) = sum(i=1, sqrtint(n), (n % i) != 0); \\ Michel Marcus, Mar 16 2014

CROSSREFS

Cf. A000005, A000196, A010052, A018253, A038548, A007491, A160812, A161205, A212119, A228813, A228814, A229940, A229942, A229944, A229950, A229951.

Sequence in context: A053250 A302242 A336915 * A116664 A295672 A308074

Adjacent sequences:  A236624 A236625 A236626 * A236628 A236629 A236630

KEYWORD

nonn

AUTHOR

Omar E. Pol, Feb 05 2014

STATUS

approved

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Last modified January 24 22:45 EST 2022. Contains 350565 sequences. (Running on oeis4.)