A035113 Numbers != 2 (mod 4) listed in order of increasing totient function phi (A000010).

1, 3, 4, 5, 8, 12, 7, 9, 15, 16, 20, 24, 11, 13, 21, 28, 36, 17, 32, 40, 48, 60, 19, 27, 25, 33, 44, 23, 35, 39, 45, 52, 56, 72, 84, 29, 31, 51, 64, 68, 80, 96, 120, 37, 57, 63, 76, 108, 41, 55, 75, 88, 100, 132, 43, 49, 69, 92, 47, 65, 104, 105, 112, 140, 144

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Examples

			phi(1)=1, phi(3)=2, phi(4)=2, phi(5)=4, ...
		

Links

• Dumitru Damian, Table of n, a(n) for n = 1..10000
• L. C. Washington, The Main Conjecture and Annihilation of Class Groups, In: Introduction to Cyclotomic Fields, Graduate Texts in Mathematics, vol 83 (1997) Springer, New York, NY.

Crossrefs

Cf. A000010, A035114.

Cf. A002181, A002202, A007614, A014197, A016825, A032447, A058277.

Programs

Python

from sympy import totient as A000010
def lov(n): return sorted([[A000010(n), n] for n in range(1,n) if n%4 != 2])
print([x[1] for x in lov(200)][:100]) # Dumitru Damian, Feb 01 2022

Extensions

More terms from James Sellers

a(43) onward corrected by Sean A. Irvine, Sep 26 2020