A236433 List of primes generated by factoring successive primary pseudoperfect numbers (A054377).

2, 2, 3, 2, 3, 7, 2, 3, 7, 43, 2, 3, 11, 23, 31, 2, 3, 11, 23, 31, 47059, 2, 3, 11, 17, 101, 149, 3109, 2, 3, 11, 23, 31, 47059, 2217342227, 1729101023519

Offset: 1

Author

Jonathan Sondow, Jan 25 2014

Keywords

• nonn
• more
• hard

Comments

It is unknown whether there are infinitely many primary pseudoperfect numbers or any odd ones.

See A054377 for other comments, references, links, etc.

For prime factors of Giuga numbers, see A236434; of terms in Sylvester's sequence, see A126263.

Examples

			2 = 2.
6 = 2 * 3.
42 = 2 * 3 * 7.
1806 = 2 * 3 * 7 * 43.
47058 = 2 *  3 * 11 * 23 * 31.
2214502422 =  2 *  3 * 11 * 23 * 31 * 47059.
52495396602 =  2 * 3 * 11 * 17 * 101 * 149 * 3109.
8490421583559688410706771261086 = 2 *  3 * 11 * 23 * 31 * 47059 * 2217342227 * 1729101023519.
		

Crossrefs

Cf. A054377, A126263, A216825, A216826, A236434.

Programs

Mathematica

A054377 = Cases[Import["https://oeis.org/A054377/b054377.txt", "Table"], {, }][[All, 2]];
First /@ Flatten[FactorInteger[A054377], 1] (* Robert Price, Mar 14 2020 *)