A037228 a(n) = phi(n) - pi(n).

1, 0, 0, 0, 1, -1, 2, 0, 2, 0, 5, -1, 6, 0, 2, 2, 9, -1, 10, 0, 4, 2, 13, -1, 11, 3, 9, 3, 18, -2, 19, 5, 9, 5, 13, 1, 24, 6, 12, 4, 27, -1, 28, 6, 10, 8, 31, 1, 27, 5, 17, 9, 36, 2, 24, 8, 20, 12, 41, -1, 42, 12, 18, 14, 30, 2, 47, 13, 25, 5, 50, 4, 51, 15, 19, 15, 39, 3, 56, 10, 32, 18, 59, 1, 41, 19

Offset

1,7

Comments

It is known that a(n) >= 0 for n >= 61.

References

D. S. Mitrinovic et al., Handbook of Number Theory, Kluwer, p. 11.

Links

Alois P. Heinz, Table of n, a(n) for n = 1..10000 (first 1000 terms from T. D. Noe)

Mathematica

Table[EulerPhi[n]-PrimePi[n], {n, 90}] (* Harvey P. Dale, Feb 02 2021 *)

Prog

(PARI) a(n) = eulerphi(n) - primepi(n); \\ Michel Marcus, Aug 08 2019

Crossrefs

Cf. A000010, A000720, A037171, A037229.

Sequence in context: A035686 A308214 A327371 * A002117 A042970 A158327

Adjacent sequences: A037225 A037226 A037227 * A037229 A037230 A037231

Keyword

sign

Author

N. J. A. Sloane.

Status

approved