A100810 a(n) = 0 if prime(n) + 2 = prime(n+1), otherwise 1.

1, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1

Offset: 1

Author

Giovanni Teofilatto, Jan 05 2005

Keywords

• easy
• nonn

Examples

			a(2) = 0 because prime(2) + 2 = 5 = prime(3).
a(3) = 0 because prime(3) + 2 = 7 = prime(4).
		

Programs

Maple

a:= n-> `if`(isprime(ithprime(n)+2), 0, 1):
seq(a(n), n=1..105);  # Alois P. Heinz, Oct 02 2020

Mathematica

Table[If[Prime[n] + 2 == Prime[n + 1], 0, 1], {n, 120}] (* Ray Chandler, Jan 09 2005 *)
If[#[[2]]-#[[1]]==2,0,1]&/@Partition[Prime[Range[110]],2,1] (* Harvey P. Dale, Mar 05 2016 *)

Formula

a(n) = 1 - A100821(n) = 1 - A062301(n+1).

Extensions

Corrected and extended by Ray Chandler, Jan 09 2005