The thing is that ignoring the 12 is cheating, you won't have this:
-2 0 4 6 10 16 18
but actually this:
-2 0 4 6 10 12 16 18
Drats!
According to
https://en.wikipedia.org/wiki/Prime_k-tuple the septuplet constellations
0, 2, 6, 8, 12, 18, 20
might sometimes be octuplet and nonuplets.
Would it be worth changing the PoW from sextuplets to "septuplets with a chance of
meatballs octuplets and nonuplets" ?
Would the current computing power in Riecoin mining be enough for world records then ?