A364028 Odd squarefree semiprimes s = p*q such that p + q and p - q are not squarefree.

65, 77, 115, 141, 159, 295, 301, 303, 319, 329, 403, 427, 473, 481, 515, 533, 581, 589, 629, 655, 671, 679, 703, 713, 717, 785, 835, 869, 871, 943, 965, 1041, 1059, 1099, 1111, 1139, 1145, 1195, 1199, 1207, 1241, 1337, 1339, 1349, 1363, 1387, 1461, 1469, 1501, 1507, 1529

Offset: 1

Author

Hugo Pfoertner, Jul 01 2023

Keywords

• nonn

Examples

			a(1) = 65 = 13*5; 13+5 = 2*3^2, 13-5 = 2^3;
a(2) = 77 = 11*7; 11+7 = 2*3^2, 11-7 = 2^2;
a(3) = 115 = 23*5; 23+5 = 2^2*7, 23-5 = 2*3^2.
		

Crossrefs

Cf. A046388, A198512, A090967.

Programs

PARI

forstep (k = 15, 1529, 2, if (omega(k)==2 && bigomega(k)==2, my (F=factorint(k)); if ( !issquarefree(F[2,1]-F[1,1]) && !issquarefree(F[2,1]+F[1,1]), print1(k,", "))))