A166173 Digit sum of n-th twin prime pair.

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.

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(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

Cf. A001359, A006512, A007953.

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