A363671 Triangular array: row n lists the numbers k such that prime(n+2)-2*k is a prime.
1, 1, 2, 2, 3, 4, 1, 3, 4, 5, 2, 3, 5, 6, 7, 1, 3, 4, 6, 7, 8, 2, 3, 5, 6, 8, 9, 10, 3, 5, 6, 8, 9, 11, 12, 13, 1, 4, 6, 7, 9, 10, 12, 13, 14, 3, 4, 7, 9, 10, 12, 13, 15, 16, 17, 2, 5, 6, 9, 11, 12, 14, 15, 17, 18, 19, 1, 3, 6, 7, 10, 12, 13, 15, 16, 18, 19
Offset: 1
Examples
First 10 rows: 1 1 2 2 3 4 1 3 4 5 2 3 5 6 7 1 3 4 6 7 8 2 3 5 6 8 9 10 3 5 6 8 9 11 12 13 1 4 6 7 9 10 12 13 14 3 4 7 9 10 12 13 15 16 17 For row 6, we have prime(8) = 19, and prime 19-2*k is prime for these k: 1, 3, 4, 6, 7, 8.
Programs
-
Mathematica
m[p_] := Select[Range[400], PrimeQ[p - 2 #] && p > 2 # &] t = Table[m[Prime[n]], {n, 3, 30}] TableForm[t] (* this sequence as an array *) Flatten[t] (* this sequence *)