A258434 n^2 - phi(n).

0, 3, 7, 14, 21, 34, 43, 60, 75, 96, 111, 140, 157, 190, 217, 248, 273, 318, 343, 392, 429, 474, 507, 568, 605, 664, 711, 772, 813, 892, 931, 1008, 1069, 1140, 1201, 1284, 1333, 1426, 1497, 1584, 1641, 1752, 1807, 1916, 2001, 2094, 2163, 2288

Offset: 1

Author

Carlos Eduardo Olivieri, May 30 2015

Keywords

• nonn
• easy

Examples

			a(5) = 21, since 5^2 = 25 and phi(5) = 4.
		

Crossrefs

Cf. A000290, A000010.

Programs

Magma

[n^2 - EulerPhi(n): n in [1..60]]; // Vincenzo Librandi, Jun 03 2015

Mathematica

Table[n^2 - EulerPhi[n], {n, 200}]

PARI

vector(50, n, n^2-eulerphi(n)) \\ Michel Marcus, May 30 2015

Formula

a(n) = A000290(n) - A000010(n).

For p prime, a(p) = A002061(p); A119959 is a subsequence. - Michel Marcus, Jun 06 2015