A079533 Floor(k - sqrt(k)) - phi(k) as k runs through the composite numbers (A002808).

0, 1, 1, 0, 2, 4, 4, 3, 4, 7, 7, 4, 7, 11, 0, 8, 3, 10, 16, 10, 7, 12, 5, 18, 13, 8, 17, 23, 17, 14, 17, 25, 0, 22, 11, 20, 28, 7, 24, 13, 22, 36, 24, 19, 24, 8, 37, 27, 16, 37, 39, 29, 26, 31, 8, 45, 39, 18, 32, 50, 11, 34, 21, 38, 56, 9, 38, 23, 38, 13, 54, 46, 29, 50, 59, 45, 46, 43, 61

Offset

1,5

Comments

It is known that a(n) >= 0.

References

D. S. Mitrinovic et al., Handbook of Number Theory, Kluwer, p. 9.

W. Sierpiński, Elementary Theory of Numbers. Państ. Wydaw. Nauk., Warsaw, 1964.

Links

Robert Israel, Table of n, a(n) for n = 1..10000

W. Sierpiński, Elementary Theory of Numbers, Warszawa 1964.

Maple

f:= proc(n) if not isprime(n) then floor(n - sqrt(n)) - numtheory:-phi(n) fi end proc:
map(f, [$4..200]); # Robert Israel, Nov 09 2023

Prog

(PARI) lista(nn) = forcomposite(n=1, nn, print1(floor(n - sqrt(n)) - eulerphi(n), ", ")); \\ Michel Marcus, Dec 12 2014

Crossrefs

Cf. A000010, A079530, A079531, A079532, A079534.

Sequence in context: A257978 A193358 A214028 * A072872 A135359 A098217

Adjacent sequences: A079530 A079531 A079532 * A079534 A079535 A079536

Keyword

nonn,look

Author

N. J. A. Sloane, Jan 23 2003

Status

approved