OFFSET
1,1
COMMENTS
All terms are odd.
FORMULA
a(n) == 1 (mod 4).
EXAMPLE
99905 = 5 * 13 * 29 * 53 = (2 * 223 * 224) + 1.
107185 = 5 * 13 * 17 * 97 = (2 * 231 * 232) + 1.
242905 = 5 * 13 * 37 * 101 = (2 * 348 * 349) + 1
MATHEMATICA
Select[Table[2*n*(n + 1) + 1, {n, 0, 1200}], FactorInteger[#][[;; , 2]] == {1, 1, 1, 1} &] (* Amiram Eldar, Mar 02 2024 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Massimo Kofler, Mar 02 2024
STATUS
approved