A065388 Record values for sigma(m) + phi(m): sum of sigma and totient is larger than for any previous number.

2, 4, 6, 9, 10, 14, 19, 22, 32, 39, 45, 50, 68, 80, 103, 106, 108, 140, 144, 184, 219, 248, 258, 284, 316, 392, 451, 528, 594, 624, 672, 808, 816, 915, 948, 955, 1088, 1266, 1440, 1640, 1704, 1824, 1843, 2020, 2031, 2176, 2208, 2610, 3072, 3304, 3512, 3888

Offset: 1

Author

Labos Elemer, Nov 05 2001

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..1288 (terms 1..500 from Harry J. Smith)

Crossrefs

Cf. A000010, A000203, A065387, A015702.

Programs

PARI

{ n=r=0; for (m=1, 10^9, x=sigma(m) + eulerphi(m); if (x > r, r=x; write("b065388.txt", n++, " ", x); if (n==500, return)) ) } \\ Harry J. Smith, Oct 17 2009

Formula

a(n) = sigma(A015702(n)) + phi(A015702(n));

a(n) = A000203(A015702(n)) + A000010(A015702(n)).

a(n) = A065387(A015702(n)). - Amiram Eldar, Mar 22 2025