A162586 Integers n for which k = (7 * (256^n - 16^n) + n^2) / (n * (8n + 7)) is an integer

2, 3, 5, 8, 9, 12, 15, 18, 20, 24, 27, 32, 45, 54, 60, 75, 78, 80, 90, 102, 110, 120, 128, 135, 162, 165, 170, 180, 192, 195, 200, 234, 243, 275, 288, 312, 330, 333, 360, 384, 408, 432, 440, 450, 465, 480, 495, 500, 513, 540, 612, 620, 624, 675, 684, 702, 729

Offset

1,1

Comments

8n + 7 is almost always prime. It is first composite for 8 * 372060 + 7 = 2976487 = 863 * 3449.

Links

Table of n, a(n) for n=1..57.

Crossrefs

Cf. A162587

Cf. A158034, A158035

Cf. A161896, A161897

Sequence in context: A091513 A060138 A139487 * A232868 A189086 A256656

Adjacent sequences: A162583 A162584 A162585 * A162587 A162588 A162589

Keyword

easy,nonn

Author

Reikku Kulon, Jul 07 2009

Status

approved