A065394 Increasing values of A065395: a(n) = A065395(A065393(n)).

1, 5, 8, 14, 22, 25, 31, 48, 56, 73, 78, 80, 138, 159, 163, 210, 240, 248, 312, 314, 474, 482, 634, 648, 684, 723, 836, 896, 978, 1026, 1134, 1184, 1320, 1344, 1410, 1424, 1608, 1686, 1760, 1776, 1862, 2226, 2624, 2824, 2936, 3024, 3120, 3280, 3460, 3660

Offset: 1

Author

Labos Elemer, Nov 05 2001

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..2000 (terms 1..500 from Harry J. Smith)

Crossrefs

Cf. A000010, A000203, A065393, A065395.

Programs

Mathematica

a=0; s=0; Do[s=DivisorSigma[1, EulerPhi[n]]-EulerPhi[DivisorSigma[1, n]]; If[s>a, a=s; Print[s]], {n, 1, 10000}]; (* Output is s. *)

PARI

{ n=r=0; for (m=1, 10^9, x=sigma(eulerphi(m)) - eulerphi(sigma(m)); if (x > r, r=x; write("b065394.txt", n++, " ", x); if (n==500, return)) ) } \\ Harry J. Smith, Oct 18 2009

Formula

a(n) = A000203(A000010(A065393(n))) - A000010(A000203(A065393(n))).