A274590 Numbers n such that n^2 - 1 is the average of two nonzero squares in exactly one way.

9, 19, 33, 35, 73, 99, 145, 161, 163, 195, 243, 393, 483, 513, 577, 721, 723, 1153, 1763, 2177, 2305, 2593, 4803, 5185, 5833, 6273, 6963, 7057, 7395, 8713, 9523, 9603, 10083, 12483, 13923, 14113, 15875, 17425, 17673, 19043, 19601, 20737, 26243

Offset: 1

Author

Altug Alkan, Jun 29 2016

Keywords

• nonn

Comments

In other words, numbers n such that n^2 - 1 is the sum of two nonzero distinct squares in exactly one way. This explains why there are many common terms between this sequence and A050797.

Examples

			9 is a term because 9^2 - 1 = (4^2 + 12^2) / 2.
		

Crossrefs

Cf. A050797.