A074039 If (n, n+2) is the k-th twin prime pair then k else 0.

0, 0, 1, 0, 2, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Offset

1,5

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

A001359(a(n)) = n, A006512(a(n)) = n+2.

Mathematica

seq[max_] := Module[{t = Select[Range[max], And @@ PrimeQ[# + {0, 2}] &], v}, v = Table[0, {max}]; v[[t]] = Range[Length[t]]; v]; seq[100] (* Amiram Eldar, Apr 06 2025 *)

Crossrefs

Cf. A001359, A006512, A049084, A074038.

Sequence in context: A356303 A238429 A332671 * A047764 A022883 A284270

Adjacent sequences: A074036 A074037 A074038 * A074040 A074041 A074042

Keyword

nonn

Author

Reinhard Zumkeller, Aug 13 2002

Status

approved