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A166173
Digit sum of n-th twin prime pair.
1
8, 12, 6, 18, 15, 12, 21, 18, 6, 18, 24, 21, 27, 24, 36, 24, 21, 27, 24, 12, 30, 21, 18, 24, 18, 33, 30, 30, 24, 33, 27, 24, 36, 42, 36, 15, 12, 21, 18, 24, 18, 21, 36, 33, 12, 21, 30, 24, 30, 42, 30, 27, 42, 48, 24, 48, 36, 48, 30, 39, 54, 24, 24, 36, 12
OFFSET
1,1
COMMENTS
Except for the first term, all the others are multiples of 3.
FORMULA
a(n)= A007953(A001359(n)) + A007953(A006512(n)).
EXAMPLE
The tenth twin prime pair is 107, 109, so a(10) = 1+0+7+1+0+9 = 18.
MATHEMATICA
Total[Flatten[IntegerDigits[#]]]&/@Select[Partition[Prime[Range[400]], 2, 1], #[[2]]- #[[1]]==2&] (* Harvey P. Dale, Dec 03 2016 *)
CROSSREFS
KEYWORD
base,nonn,easy
AUTHOR
Parthasarathy Nambi, Oct 09 2009
EXTENSIONS
Corrected by Harvey P. Dale, Dec 03 2016
STATUS
approved