A120439 Average of twin-prime pairs modulo 5.

-1, 1, 2, -2, 0, 2, 0, 2, 2, -2, -2, 0, 0, 2, -2, -2, 0, 0, 2, 2, -2, 0, 2, 2, 2, 0, 0, -2, 2, 0, 0, 2, -2, -2, 2, 0, 2, 0, 2, 2, 2, 0, -2, 0, 2, 0, -2, 2, 2, -2, -2, 0, -2, -2, 2, -2, 2, -2, 2, 0, -2, -2, 2, -2, 2, 0, 2, -2, -2, 0, 0, 2, 0, 2, -2, -2, 2, 0, 0, 2, 0, 0, 0, -2, 2, -2, 0, 0, 0, 2, 0, 2, -2, -2, 0, -2, 2, 2, -2, 2, 2, -2, 0, 2, 0, 0, 2, -2, -2, -2, 0

Offset

1,3

Comments

The FTAW comment in A120438 means, a(n) = A120438(n) for n>=3 because all entries in A014574(n>=3) end on 0, 2, or 8, never on 4 or 6. - R. J. Mathar, May 22 2026

Links

Table of n, a(n) for n=1..111.

Example

First twin-prime average = 4 (=-1+1*5): a(1) = -1.
Second twin-prime average = 6 (=1+1*5): a(2) = +1.
Third twin-prime average = 12 (=2+2*5): a(3) = +2.

Mathematica

Mod[#, 5]&/@(Mean/@Select[Partition[Prime[Range[1000]], 2, 1], Last[#]- First[#]==2&])/.{4->-1, 3->-2} (* Harvey P. Dale, Dec 18 2013 *)

Crossrefs

Cf. A014574, A120438.

Sequence in context: A122157 A080378 A243865 * A248512 A352564 A353596

Adjacent sequences: A120436 A120437 A120438 * A120440 A120441 A120442

Keyword

sign

Author

Greg Huber, Jul 18 2006

Status

approved