A077063 Squarefree kernel of prime(n) - 1.

1, 2, 2, 6, 10, 6, 2, 6, 22, 14, 30, 6, 10, 42, 46, 26, 58, 30, 66, 70, 6, 78, 82, 22, 6, 10, 102, 106, 6, 14, 42, 130, 34, 138, 74, 30, 78, 6, 166, 86, 178, 30, 190, 6, 14, 66, 210, 222, 226, 114, 58, 238, 30, 10, 2, 262, 134, 30, 138, 70, 282, 146, 102, 310, 78, 158

Offset: 1

Author

Reinhard Zumkeller, Oct 23 2002

Keywords

• nonn

Examples

			a(25) = rad(prime(25)-1) = rad(97-1) = rad(3*2^5) = 6.
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A006093, A007947, A077066.

Programs

Haskell

a077063 = a007947 . a006093  -- Reinhard Zumkeller, Sep 04 2013

Maple

A077063 := proc(n)
    A007947(A006093(n)) ;
end proc:
seq(A077063(n),n=1..30) ; # R. J. Mathar, Jan 13 2021

Mathematica

rad[n_] := Times @@ (First@# & /@ FactorInteger[n]); rad /@
Select[Range[400], PrimeQ[# + 1] &] (* Amiram Eldar, Dec 29 2020 *)
Times@@FactorInteger[#-1][[;;,1]]&/@Prime[Range[70]] (* Harvey P. Dale, Mar 16 2023 *)

PARI

a(n)=my(f=factor(prime(n)-1)[,1]); prod(i=1,#f,f[i]) \\ Charles R Greathouse IV, Aug 21 2013

Formula

a(n) = A007947(A006093(n)).

Extensions

Wrong formula removed by Amiram Eldar, Dec 29 2020