A145747 a(n) is the smallest number m such that phi(m)+sigma(m)=n*pi(m).

3, 2, 14, 26, 55, 30, 56, 329, 626, 366, 340, 558, 288, 552, 828, 3496, 6928, 2430, 81809, 3920, 3432, 8680, 48380, 23430, 2520, 144020, 435056, 21384, 728096, 188376, 11802175, 97320, 54057938, 89700, 349752, 1143492, 11286632, 490752

Offset

3,1

Comments

a(47) is greater than 4*10^8.

Links

Table of n, a(n) for n=3..40.

Mathematica

a[n_]:=(For[m=1, DivisorSigma[1, m]+EulerPhi[m]!=n EulerPhi[m], m++ ]; m); Do[Print[a[n]], {n, 3, 46}]

Crossrefs

Cf. A015704.

Sequence in context: A324661 A163355 A214885 * A055234 A291051 A342640

Adjacent sequences: A145744 A145745 A145746 * A145748 A145749 A145750

Keyword

nonn

Author

Farideh Firoozbakht, Oct 30 2008

Status

approved