OFFSET
1,2
COMMENTS
If the extended Goldbach conjecture is true, such a pair exists in row n for all n >= 4. - Nathaniel Johnston, Apr 18 2011
LINKS
Nathaniel Johnston, Table of n, a(n) for n = 1..10000
Wolfram MathWorld, Goldbach Conjecture
EXAMPLE
Triangle begins:
1
2
3
3, . 5
3, . . . 7
. . 5, . 7, . .
3, . . . . . . . 11
3, . 5, . . . . . 11, . 13
. . 5, . 7, . . . 11, . 13, . .
3, . . . 7, . . . . . 13, . . . 17
MAPLE
print(1):print(2):print(3):for n from 1 to 15 do for k from 1 to 2*n-1 do if(not k=n and (isprime(k) and isprime(2*n-k)))then print(k):fi:od:od: # Nathaniel Johnston, Apr 18 2011
MATHEMATICA
Table[n + Union@ Join[#, -#] /. {} -> {n} &@ Select[DeleteCases[n - Prime@ Range[2, PrimePi@ n], 0], AllTrue[n + # {-1, 1}, PrimeQ] &], {n, 20}] // Flatten (* Michael De Vlieger, Feb 03 2019 *)
CROSSREFS
KEYWORD
easy,nonn,tabf
AUTHOR
Omar E. Pol, Jan 14 2009, Jan 16 2009
EXTENSIONS
a(24)-a(70) from Nathaniel Johnston, Apr 18 2011
STATUS
approved