A256840 Primes of form n^2 + 20736.

20857, 21577, 21961, 23761, 27961, 28657, 29017, 29761, 30937, 33961, 34897, 37897, 41761, 42937, 49297, 51361, 60337, 62761, 65257, 80761, 83737, 93097, 107761, 111337, 113761, 122497, 132961, 142537, 151057, 164377, 173617, 181537, 188017, 192961, 218761

Offset: 1

Author

Reinhard Zumkeller, Apr 11 2015

Keywords

• nonn

Comments

Conjecture: sequence is infinite.

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
• J. Gebel, Integer points on Mordell curves [Cached copy, after the original web site tnt.math.se.tmu.ac.jp was shut down in 2017]

Crossrefs

Cf. A010051, A000290; subsequence of A028916.

Primes of form n^2+b^4, b fixed: A002496 (b=1), A243451 (b=2), A256775 (b=3), A256776 (b=4), A256777 (b=5), A256834 (b=6), A256835 (b=7), A256836 (b=8), A256837 (b=9), A256838 (b=10), A256839 (b=11), A256841 (b=13).

Programs

Haskell

a256840 n = a256840_list !! (n-1)
a256840_list = [x | x <- map (+ 20736) a000290_list, a010051' x == 1]