OFFSET
1,1
COMMENTS
EXAMPLE
41 and 43 are in the sequence because they form a twin prime pair in which 41 has a digital root of 5 and 43 has a digital root of 7. Likewise 59 and 61 form a twin prime pair where 59 has a digital root of 5 and 61 has one of 7.
MATHEMATICA
dRoot[n_] := 1 + Mod[n - 1, 9]; tw = Select[Prime[Range[1000]], PrimeQ[# + 2] &]; Select[Union[tw, tw + 2], MemberQ[{5, 7}, dRoot[#]] &] (* T. D. Noe, Dec 10 2013 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Gary Croft, Dec 01 2013
STATUS
approved