

A166173


Digit sum of nth 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
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OFFSET

1,1


COMMENTS

Except for the first term, all the others are multiples of 3.


LINKS

Table of n, a(n) for n=1..65.
Chris Caldwell, The First 100,000 Twin Primes


FORMULA

a(n)= A007953(A001359(n)) + A007953(A006512).


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

Cf. A001359
Sequence in context: A072900 A203836 A220665 * A014453 A160862 A152077
Adjacent sequences: A166170 A166171 A166172 * A166174 A166175 A166176


KEYWORD

base,nonn,easy


AUTHOR

Parthasarathy Nambi, Oct 09 2009


EXTENSIONS

Corrected by Harvey P. Dale, Dec 03 2016


STATUS

approved



