OFFSET
1,1
EXAMPLE
2*3 - 7 = -1.
2*2*3 - 7 = 5, prime; 2*2*3 + 7 = 19, prime; so for n=2 k=2.
MATHEMATICA
Primorial[n_] := Product[ Prime[i], {i, n}]; f[n_] := Block[{k = 1, p = Primorial[n], q = Prime[n + 2]}, While[k*p - q < 2 || !PrimeQ[k*p - q] || !PrimeQ[k*p + q], k++ ]; k]; Table[ f[n], {n, 63}] (* Robert G. Wilson v, Aug 31 2004 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Pierre CAMI, Aug 27 2004
EXTENSIONS
More terms from Robert G. Wilson v, Aug 31 2004
STATUS
approved