A120875 - OEIS

%I #29 Nov 14 2015 03:59:23

%S 14,34,142,322,898,1762,3598,5182,10402,11662,19042,22498,32398,36862,

%T 39202,51982,57598,72898,79522,97342,121102,176398,186622,213442,

%U 272482,324898,359998,381922,412162,435598,656098,675682,685582,736162

%N Product of twin primes minus 1.

%C This sequence is a subsequence of A023515.

%H Jason Kimberley (using T. Noe's b037074), <a href="/A120875/b120875.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A037074(n)-1 = (A014574(n))^2 -2 = A075369(n)-2.

%F a(n) = 2*A120876(n). - _Jason Kimberley_, Oct 23 2015

%F a(n) = 36*A002822(n-1)^2-2, for n>1. - _Jason Kimberley_, Oct 23 2015

%F a(n) = A023515(A107770(n)). - _Jason Kimberley_, Oct 23 2015

%t Times[#, # + 2] - 1 & /@ Select[Prime@ Range@ 150, PrimeQ[# + 2] &] (* _Michael De Vlieger_, Oct 23 2015 *)

%o (PARI) for(n=1, 200, if(prime(n+1)-prime(n)==2, print1(prime(n)*prime(n+1)-1", "))) \\ _Altug Alkan_, Oct 23 2015

%Y Cf. A002822, A023515, A037074, A075369, A120876.

%K nonn

%O 1,1

%A _Lekraj Beedassy_, Jul 09 2006