A329584 phi(A327922(n))/4, for n >= 1, with phi = A000010 (Euler's totient).

1, 3, 2, 4, 3, 5, 7, 5, 6, 9, 6, 10, 6, 8, 13, 10, 9, 15, 9, 12, 11, 18, 10, 15, 16, 14, 22, 18, 15, 18, 24, 15, 25, 12, 27, 18, 28, 22, 18, 24, 20, 25, 21, 27, 18, 34, 23, 30, 28, 21, 37, 24, 30, 39, 26, 33, 20, 39, 27, 43, 30, 29, 45, 30, 36, 40, 27, 48

Offset: 1

Author

Wolfdieter Lang, Nov 17 2019

Keywords

• nonn
• easy

Comments

This sequence applies to the odd m >= 3 numbers collected in A327922 with 4 dividing phi(2*m) = phi(m). The analog for even m is: every even numbers m >= 4 has even phi(2*m)/2 = A062570(m/2) = 2*A055034(m/2), This means that phi(2*m)/4 = A055034(m/2), for every even m >= 4.

Examples

			n = 1: A327922(1) = 5,  A000010(5) = 4, hence a(1) = 1.
n = 5: A327922(5) = 21 = 3*7,  A000010(21) = 2*6 = 12, hence a(5) = 3.
		

Crossrefs

Cf. A000010, A055034, A062570, A327922.

Programs

Mathematica

Select[EulerPhi[Range[3, 200, 2]]/4, IntegerQ] (* Amiram Eldar, Nov 17 2019 *)

Formula

a(n) = A000010(A327922(n))/4, for n >= 1.