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A195104 Smallest prime p such that p*t(n) +- 1 is a twin prime pair, where t(n)=A014574(n) is the n-th twin prime average. 1

%I

%S 3,2,5,11,2,11,3,29,101,199,29,7,13,11,29,71,13,3,71,101,29,43,79,5,

%T 11,11,5,29,61,2,2,11,19,11,29,5,11,7,41,19,181,19,59,5,11,7,29,11,41,

%U 179,41,13,61,181,19,241,139,331,271,3,59,5,41,89,19,2,5,131,59,5,5,509,2

%N Smallest prime p such that p*t(n) +- 1 is a twin prime pair, where t(n)=A014574(n) is the n-th twin prime average.

%C a(n) = 2 for n in A158866. - _Robert Israel_, Mar 07 2021

%H Robert Israel, <a href="/A195104/b195104.txt">Table of n, a(n) for n = 1..10000</a>

%e a(4)=11 because 11*A014574(4) +- 1 = 11*18 +- 1 = 198 +- 1 is a twin prime pair, A014574(4) +- 1 = 18 +- 1 is also a twin prime pair, and 11 is prime.

%p A195104 := proc(n)

%p k := A014574(n) ;

%p for i from 1 do

%p p := ithprime(i) ;

%p if isprime(p*k-1) and isprime(p*k+1) then

%p return p;

%p end if;

%p end do:

%p end proc:

%p seq(A195104(n),n=1..60) ; # _R. J. Mathar_, Dec 16 2011

%Y Cf. A014574, A158866.

%K nonn

%O 1,1

%A _Juri-Stepan Gerasimov_, Dec 16 2011

%E a(64) corrected by _Robert Israel_, Mar 07 2021

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Last modified June 21 16:42 EDT 2021. Contains 345365 sequences. (Running on oeis4.)