A083247 Numbers k such that A000010(k) > A045763(k) > A000005(k).

14, 20, 21, 22, 26, 27, 28, 32, 33, 34, 35, 38, 39, 44, 45, 46, 49, 51, 52, 55, 57, 58, 62, 63, 64, 65, 68, 69, 74, 75, 76, 77, 81, 82, 85, 86, 87, 91, 92, 93, 94, 95, 99, 106, 111, 115, 116, 117, 118, 119, 121, 122, 123, 124, 125, 128, 129, 133, 134, 135, 141, 142

Offset

1,1

Comments

Primes are not terms since A045763(p) = 0 < A000005(p) = 2 for a prime p.

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

k = 99 is a term since d(k) = 6, phi(k) = 60, unrelateds(k) = 99 - 6 - 60 + 1 = 34, and 60 > 34 > 6 holds.

Mathematica

Do[r=EulerPhi[n]; d=DivisorSigma[0, n]; u=n-r-d+1; If[Greater[r, u]&&Greater[u, d], Print[n, {d, r, u}]], {n, 1, 1000}]

Prog

(PARI) is(n)=my(r=eulerphi(n), d=numdiv(n), u=n-r-d+1); r>u && u>d \\ Charles R Greathouse IV, Feb 21 2013

Crossrefs

Cf. A000005, A000010, A045763, A073757, A083243, A083244, A083245, A083246, A083248, A020488.

Sequence in context: A144080 A006576 A349262 * A255346 A074851 A193672

Adjacent sequences: A083244 A083245 A083246 * A083248 A083249 A083250

Keyword

nonn,less

Author

Labos Elemer, May 07 2003

Status

approved