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%I #13 Mar 06 2024 15:46:29
%S 99905,107185,242905,350285,363805,372385,433381,569245,590785,630565,
%T 692665,752765,907205,942565,1026745,1076045,1090765,1105585,1227745,
%U 1275205,1333345,1467185,1526005,1647113,1661665,1761565,1810705,1911013,2026085,2317705,2395861,2470865
%N Centered square numbers which are products of four distinct primes (or tetraprimes).
%C All terms are odd.
%F a(n) == 1 (mod 4).
%e 99905 = 5 * 13 * 29 * 53 = (2 * 223 * 224) + 1.
%e 107185 = 5 * 13 * 17 * 97 = (2 * 231 * 232) + 1.
%e 242905 = 5 * 13 * 37 * 101 = (2 * 348 * 349) + 1
%t Select[Table[2*n*(n + 1) + 1, {n, 0, 1200}], FactorInteger[#][[;; , 2]] == {1, 1, 1, 1} &] (* _Amiram Eldar_, Mar 02 2024 *)
%Y Intersection of A046386 and A001844.
%K nonn
%O 1,1
%A _Massimo Kofler_, Mar 02 2024
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