A371016 Centered square numbers which are semiprime.

25, 85, 145, 221, 265, 365, 481, 545, 685, 841, 1405, 1513, 1985, 2245, 2813, 2965, 3281, 3785, 3961, 4141, 4705, 5305, 5513, 5941, 6161, 6385, 6613, 7081, 7813, 8065, 8321, 9113, 9385, 10805, 11101, 11401, 11705, 12013, 12961, 13285, 13945, 16021, 17113, 17861, 19405, 22261, 23113, 24865

Offset: 1

Author

Massimo Kofler, Mar 08 2024

Keywords

• nonn

Comments

All terms are odd numbers.

Examples

			25 = 5 * 5 = (2 * 3 * 4) + 1.
85 = 5 * 17 = (2 * 6 * 7) + 1.
145 = 5 * 29 = (2 * 8 * 9) + 1.
		

Crossrefs

Intersection of A001358 and A001844.

Programs

Mathematica

Select[Table[2*n*(n + 1) + 1, {n, 0, 120}], PrimeOmega[#] == 2 &] (* Amiram Eldar, Mar 08 2024 *)