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A173386 The absolute values of n-th natural noncomposite number minus n-th number k such that 6*k-+1 is a twin prime pair.

%I A173386 #7 Dec 08 2015 02:01:25
%S A173386 0,0,0,0,0,1,1,0,1,0,4,1,5,8,5,7,8,12,9,9,1,1,2,4,6,3,2,4,3,26,24,11,
%T A173386 12,10,31,23,24,20,19,25,32,34,34,26,27,41,43,36,25,41,41,45,44,46,47,
%U A173386 55,50,53,54,56,57,64,55,45,44,44,56,47,48,43,48,72,73,76,75,73,72,76,70
%N A173386 The absolute values of n-th natural noncomposite number minus n-th number k such that 6*k-+1 is a twin prime pair.
%F A173386 a(n) = abs(A008578(n) - A002822(n)).
%p A173386 Contribution from _R. J. Mathar_, Mar 09 2010: (Start)
%p A173386 A008578 := proc(n) if n= 1 then 1; else ithprime(n-1) ; end if; end proc:
%p A173386 A002822 := proc(n) if n = 1 then 1; else for a from procname(n-1)+1 do if isprime(6*a-1) and isprime(6*a+1) then return a; fi; end do ; end if; end proc:
%p A173386 A173386 := proc(n) abs(A008578(n)-A002822(n)) ; end proc:
%p A173386 seq(A173386(n),n=1..90) ; (End)
%Y A173386 Cf. A002822, A008578.
%K A173386 nonn
%O A173386 1,11
%A A173386 _Juri-Stepan Gerasimov_, Feb 17 2010