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%I #14 Dec 02 2016 11:07:08
%S 6,8,8,8,26,17,26,17,8,17,17,26,26,26,17,26,35,35,26,26,8,35,26,17,26,
%T 35,44,26,17,35,35,35,35,26,35,26,17,26,26,26,17,35,26,35,26,35,26,17,
%U 26,17,35,35,26,26,35,35,26,35,26,35,26,26,26,35,26,44,35,26,26,35,44,35
%N Sum of digits of product of twin primes A037074.
%C Conjecture: except for the initial term, each term is one less than a multiple of 9. - _Harvey P. Dale_, Dec 02 2016
%H Harvey P. Dale, <a href="/A136050/b136050.txt">Table of n, a(n) for n = 1..5000</a>
%F a(n) = A007953(A037074(n)). - _Michel Marcus_, Nov 04 2013
%e The product of the first twin primes is 15=3*5, and sum of digits of 15 is 6.
%t a = {6}; Do[If[PrimeQ[6n - 1] && PrimeQ[6n + 1], c = IntegerDigits[36n^2 - 1]; b = Total[c]; AppendTo[a, b]], {n, 400}]; a
%t Total[IntegerDigits[Times@@#]]&/@Select[Partition[Prime[Range[500]],2,1], #[[2]]- #[[1]]==2&] (* _Harvey P. Dale_, Dec 02 2016 *)
%o (PARI) lista(nn) = for (x=1, nn, if(prime(x+1)-prime(x)==2, print1(sumdigits(prime(x)*prime(x+1)), ", "))); \\ _Michel Marcus_, Nov 04 2013
%Y Cf. A002822, A037074, A007953, A136017.
%K nonn,base
%O 1,1
%A _Artur Jasinski_, Dec 12 2007
%E First term a(1)=6 inserted by _Michel Marcus_, Nov 04 2013
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