|
|
A370795
|
|
Centered square numbers which are products of four distinct primes (or tetraprimes).
|
|
0
|
|
|
99905, 107185, 242905, 350285, 363805, 372385, 433381, 569245, 590785, 630565, 692665, 752765, 907205, 942565, 1026745, 1076045, 1090765, 1105585, 1227745, 1275205, 1333345, 1467185, 1526005, 1647113, 1661665, 1761565, 1810705, 1911013, 2026085, 2317705, 2395861, 2470865
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
All terms are odd.
|
|
LINKS
|
|
|
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
|
|
|
STATUS
|
approved
|
|
|
|