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A078579 Squarefree kernel of the average of n-th twin prime pair. 3
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified May 27 12:49 EDT 2022. Contains 354097 sequences. (Running on oeis4.)