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A065864 Remainder when n is divided by the number of nonprimes not exceeding n. 7
0, 0, 0, 0, 1, 0, 1, 0, 4, 4, 5, 5, 6, 6, 6, 6, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 10, 10, 11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 13, 13, 14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16, 17, 17, 18, 18, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20, 21, 21, 21, 21, 21, 21 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,9

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = n mod (n-pi(n)) = n mod (n-A000720(n)) = n mod A062298(n).

EXAMPLE

For n=100, pi(100)=25, so a(100) = 100 mod (100-25) = 25.

MATHEMATICA

Table[Mod[n, n - PrimePi@ n], {n, 78}] (* or *)

Table[Mod[n, Count[Range@ n, k_ /; ! PrimeQ@ k]], {n, 78}] (* Michael De Vlieger, Jan 01 2017 *)

PROG

(PARI) { for (n = 1, 1000, a=n%(n - primepi(n)); write("b065864.txt", n, " ", a) ) } \\ Harry J. Smith, Nov 02 2009

CROSSREFS

Cf. A000040, A004648, A062298, A065133, A065134, A065858-A065864.

Sequence in context: A244234 A237449 A003869 * A120205 A257291 A152465

Adjacent sequences:  A065861 A065862 A065863 * A065865 A065866 A065867

KEYWORD

nonn

AUTHOR

Labos Elemer, Nov 26 2001

STATUS

approved

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Last modified March 19 19:45 EDT 2019. Contains 321331 sequences. (Running on oeis4.)