A033871 Divisors = 3 (mod 4) of Descartes's 198585576189.

3, 7, 11, 19, 39, 63, 91, 99, 143, 147, 171, 183, 231, 247, 363, 399, 427, 507, 539, 627, 671, 819, 847, 931, 1083, 1159, 1183, 1287, 1463, 1859, 1911, 2223, 2299, 2379, 2527, 3003, 3211, 3843, 3971, 4719, 4851, 5187, 5551, 6039

Offset: 1

Author

Naohiro Nomoto

Keywords

• easy
• fini
• nonn
• full

Comments

The number 198585576189 (which is the only known odd spoof-perfect number, cf. A174292) has 486 divisors, 240 of which are congruent to 3 modulo 4. - M. F. Hasler, Feb 17 2017

Examples

			198585576189 = 3^2 * 7^2 * 11^2 * 13^2 * 19^2 * 61.
		

Links

• M. F. Hasler, Table of n, a(n) for n = 1..240

Crossrefs

Cf. A033870, A222262.

Programs

Mathematica

Select[Divisors[198585576189],Mod[#,4]==3&] (* Harvey P. Dale, Jan 07 2023 *)

PARI

lista() = {fordiv(198585576189, d, if (d % 4 == 3, print1(d, ", ")));} \\ Michel Marcus, Jul 14 2013

PARI

select(d->d%4==1, divisors(198585576189)) \\ M. F. Hasler, Feb 17 2017

Extensions

Corrected by Michel Marcus, Jul 14 2013