A033871 - OEIS

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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

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OFFSET

1,1

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

LINKS

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

EXAMPLE

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

MATHEMATICA

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

PROG

(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

CROSSREFS

Cf. A033870, A222262.

Sequence in context: A132447 A132449 A132453 * A060288 A355139 A191245