This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A380882 #13 Mar 02 2025 23:54:35
%S A380882 1105,2665,3445,7565,8845,14965,15665,16745,17485,18241,20605,22685,
%T A380882 23545,27145,28085,32005,32513,35113,37265,48985,50245,50881,55445,
%U A380882 56785,62305,71065,74885,78013,80401,81205,84461,85285,88621,89465,109045,111865,113765,116645,118585,119561
%N A380882 Centered square numbers which are sphenic numbers.
%C A380882 a(n) == 1 (mod 4).
%e A380882 1105 = 5 * 13* 17 which is the 24-th centered square number.
%e A380882 18241 = 17 * 29 * 37 which is the 96-th centered square number.
%e A380882 32513 = 13 * 41 * 61 which is 128-th centered square number.
%t A380882 Select[Table[2*n*(n+1) + 1, {n, 0, 250}], FactorInteger[#][[;; , 2]] == {1, 1, 1} &] (* _Amiram Eldar_, Feb 07 2025 *)
%Y A380882 Intersection of A007304 and A001844.
%Y A380882 Cf. A027862, A371016, A370795.
%K A380882 nonn
%O A380882 1,1
%A A380882 _Massimo Kofler_, Feb 07 2025