OFFSET
1,1
COMMENTS
If this sequence has no common terms with A324647, or no terms common with A324727, then there are no odd perfect numbers.
The first 16 terms factored:
7425 = 3^3 * 5^2 * 11,
76545 = 3^7 * 5 * 7,
92565 = 3^2 * 5 * 11^2 * 17,
236925 = 3^6 * 5^2 * 13,
831105 = 3^2 * 5 * 11 * 23 * 73,
954765 = 3^2 * 5 * 7^2 * 433,
1401345 = 3^2 * 5 * 11 * 19 * 149,
2011905 = 3^3 * 5 * 7 * 2129,
2048445 = 3^2 * 5 * 7^2 * 929,
2129985 = 3^2 * 5 * 11 * 13 * 331,
2253825 = 3^5 * 5^2 * 7 * 53,
2445345 = 3^2 * 5 * 7^2 * 1109,
2621745 = 3^2 * 5 * 7^2 * 29 * 41,
2974725 = 3^4 * 5^2 * 13 * 113,
3283245 = 3^2 * 5 * 7^2 * 1489,
3847725 = 3^2 * 5^2 * 7^2 * 349.
LINKS
MATHEMATICA
Select[Range[1, 10^7, 2], BitAnd[#, DivisorSigma[1, #] - #] == # &] (* Michael De Vlieger, Jun 22 2019, after Vincenzo Librandi at A318458 *)
PROG
(PARI) isok(k) = (k%2) && (bitand(k, sigma(k)-k) == k); \\ Michel Marcus, Jul 18 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Apr 19 2019
STATUS
approved