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

1,1

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.

Links

Table of n, a(n) for n=1..43.

Example

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

Crossrefs

Cf. A050797.

Sequence in context: A190513 A190576 A250663 * A051811 A034056 A195042

Adjacent sequences: A274587 A274588 A274589 * A274591 A274592 A274593

Keyword

nonn

Author

Altug Alkan, Jun 29 2016

Status

approved