|
%I #10 Apr 03 2023 10:36:11
%S 8,12,6,18,15,12,21,18,6,18,24,21,27,24,36,24,21,27,24,12,30,21,18,24,
%T 18,33,30,30,24,33,27,24,36,42,36,15,12,21,18,24,18,21,36,33,12,21,30,
%U 24,30,42,30,27,42,48,24,48,36,48,30,39,54,24,24,36,12
%N Digit sum of n-th twin prime pair.
%C Except for the first term, all the others are multiples of 3.
%H Chris Caldwell, <a href="https://t5k.org/lists/small/100ktwins.txt">The First 100,000 Twin Primes</a>
%F a(n)= A007953(A001359(n)) + A007953(A006512).
%e The tenth twin prime pair is 107, 109, so a(10) = 1+0+7+1+0+9 = 18.
%t Total[Flatten[IntegerDigits[#]]]&/@Select[Partition[Prime[Range[400]],2,1], #[[2]]- #[[1]]==2&] (* _Harvey P. Dale_, Dec 03 2016 *)
%Y Cf. A001359
%K base,nonn,easy
%O 1,1
%A _Parthasarathy Nambi_, Oct 09 2009
%E Corrected by _Harvey P. Dale_, Dec 03 2016
|
