A078579 Squarefree kernel of the average of n-th twin prime pair.

2, 6, 6, 6, 30, 42, 30, 6, 102, 6, 138, 30, 30, 6, 66, 114, 30, 30, 282, 78, 174, 210, 6, 462, 174, 570, 30, 618, 642, 330, 30, 822, 138, 858, 42, 510, 258, 210, 354, 546, 6, 1230, 426, 1290, 1302, 330, 714, 66, 1482, 186, 402, 30, 834, 1698, 1722, 894, 78

Offset

1,1

Links

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

Formula

a(n) = A007947(A014574(n)).

a(A070195(n)) = A070195(n).

Mathematica

midQ[n_] := PrimeQ[n-1] && PrimeQ[n+1]; f[n_] := Times @@ FactorInteger[n][[;; , 1]]; f /@ Select[Range[2000], midQ] (* Amiram Eldar, Nov 03 2019 *)

Crossrefs

Cf. A007947, A014574, A070195, A078580.

Sequence in context: A120627 A089879 A087651 * A110936 A197850 A226043

Adjacent sequences: A078576 A078577 A078578 * A078580 A078581 A078582

Keyword

nonn

Author

Reinhard Zumkeller, Nov 29 2002

Status

approved