A302826 a(n) is number of primes of form k^2 + n - k for 0 < k < n.
1, 2, 0, 4, 0, 4, 0, 2, 0, 10, 0, 4, 0, 3, 0, 16, 0, 6, 0, 5, 0, 10, 0, 10, 0, 5, 0, 13, 0, 14, 0, 3, 0, 10, 0, 16, 0, 7, 0, 40, 0, 8, 0, 6, 0, 26, 0, 12, 0, 9, 0, 19, 0, 14, 0, 9, 0, 34, 0, 21, 0, 5, 0, 19, 0, 36, 0, 13, 0, 28, 0, 18, 0, 7, 0, 31, 0, 18, 0, 19, 0, 34, 0, 15
Offset: 2
Keywords
Examples
Primes of form k^2 + n - k for 0 < k < n:
n\k| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 |a(n)
---+------------------------------------------------------------------------+----
2| 2; | 1
3| 3, 5; | 2
4| | 0
5| 5, 7, 11, 17; | 4
6| | 0
7| 7, , 13, 19, , 37; | 4
8| | 0
9| , 11, , , 29, , , ; | 2
10| | 0
11| 11, 13, 17, 23, 31, 41, 53, 67, 83, 101; | 10
12| | 0
13| 13, , 19, , , 43, , , , 103, , ; | 4
14| | 0
15| , 17, , , , , , 71, , , , , , 197; | 3
16| | 0
17| 17, 19, 23, 29, 37, 47, 59, 73, 89, 107, 127, 149, 173, 199, 227, 257; | 16
Links
- Seiichi Manyama, Table of n, a(n) for n = 2..10000
- Eric Weisstein's World of Mathematics, Lucky Number of Euler
- Wikipedia, Lucky numbers of Euler