A275988 - OEIS

%I #12 Sep 03 2016 23:52:36

%S 3,10,18,30,36,48,56,70,80,84,106,114,126,138,150,170,174,190,202,210,

%T 234,238,264,270,282,296,316,326,340,350,360,372,386,418,422,442,450,

%U 456,476,486,498,520,536,550,564,588,600,604,626,634,650,672,696,702,720,734,750,762,774

%N a(n) = prime(3n) - prime(n).

%F a(n) = A031336(n) - A000040(n).

%e For n=3, prime(3n) = 23, and prime(n) = 5, therefore a(3) = 23 - 5 = 18.

%t Table[Prime[3n] - Prime[n], {n, 1, 100}]

%o (PARI) a(n) = prime(3*n) - prime(n); \\ _Michel Marcus_, Aug 18 2016

%Y Cf. A000040, A031336, A072473.

%K nonn

%O 1,1

%A _Terry D. Grant_, Aug 15 2016