A141175 Duplicate of A007522.

7, 23, 31, 47, 71, 79, 103, 127, 151, 167, 191, 199, 223, 239, 263, 271, 311, 359, 367, 383, 431, 439, 463, 479, 487, 503, 599, 607, 631, 647, 719, 727, 743, 751, 823, 839, 863, 887, 911, 919, 967, 983, 991, 1031, 1039, 1063, 1087, 1103, 1151, 1223, 1231

Offset: 1

Author

Laura Caballero Fernandez, Lourdes Calvo Moguer, Maria Josefa Cano Marquez, Oscar Jesus Falcon Ganfornina and Sergio Garrido Morales (oscfalgan(AT)yahoo.es), Jun 12 2008

Keywords

• dead

Comments

Original title was "Primes of the form -x^2 + 4xy + 4y^2 (as well as of the form 7x^2 + 12xy + 4y^2)."

R. J. Mathar was the first to wonder if this entry is a duplicate. By elementary means, I very easily proved that all primes of this form are also of the form 8n + 7 (which is A007522). Then Don Reble demonstrated that each prime of the form 8n + 7 has a corresponding representation as -x^2 + 4xy + 4y^2. Therefore the two sequences are in fact the same. - Alonso del Arte, Nov 21 2016

Extensions

More terms from Colin Barker, Apr 05 2015