A073065 - OEIS

%I #9 Jun 24 2018 17:59:07

%S 6,15,55,119,341,533,1003,1273,1909,3161,3937,5809,7339,8213,9917,

%T 12773,16343,17263,22177,25063,26791,31679,35773,41029,49373,55247,

%U 57989,62809,65291,69721,90043,96809,105901,110783,127991,132427,144283,157621,165497

%N a(n) = prime(n) * prime(prime(n)).

%e Prime numbers are 2,3,5,7,11,13,17,... 2nd prime is 3, 3rd prime is 5 and the 5th prime is 11, so we get 2*3=6, 3*5=15, 5*11=55...

%t #*Prime[#]&/@Prime[Range[40]] (* _Harvey P. Dale_, Jun 24 2018 *)

%o (PARI) a(n) = prime(n) * prime(prime(n)) \\ _Michel Marcus_, Jun 26 2013

%Y Cf. A000040, A073136.

%K easy,nonn

%O 1,1

%A Y. Kelly Itakura (yitkr(AT)mta.ca), Aug 22 2002