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A077063 Squarefree kernel of prime(n) - 1. 6

%I #19 Mar 16 2023 15:16:10

%S 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,

%T 102,106,6,14,42,130,34,138,74,30,78,6,166,86,178,30,190,6,14,66,210,

%U 222,226,114,58,238,30,10,2,262,134,30,138,70,282,146,102,310,78,158

%N Squarefree kernel of prime(n) - 1.

%H Reinhard Zumkeller, <a href="/A077063/b077063.txt">Table of n, a(n) for n = 1..10000</a>

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

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

%p A077063 := proc(n)

%p A007947(A006093(n)) ;

%p end proc:

%p seq(A077063(n),n=1..30) ; # _R. J. Mathar_, Jan 13 2021

%t rad[n_] := Times @@ (First@# & /@ FactorInteger[n]); rad /@

%t Select[Range[400], PrimeQ[# + 1] &] (* _Amiram Eldar_, Dec 29 2020 *)

%t Times@@FactorInteger[#-1][[;;,1]]&/@Prime[Range[70]] (* _Harvey P. Dale_, Mar 16 2023 *)

%o (PARI) a(n)=my(f=factor(prime(n)-1)[,1]); prod(i=1,#f,f[i]) \\ _Charles R Greathouse IV_, Aug 21 2013

%o (Haskell)

%o a077063 = a007947 . a006093 -- _Reinhard Zumkeller_, Sep 04 2013

%Y Cf. A006093, A007947, A077066.

%K nonn

%O 1,2

%A _Reinhard Zumkeller_, Oct 23 2002

%E Wrong formula removed by _Amiram Eldar_, Dec 29 2020

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Last modified March 28 12:59 EDT 2024. Contains 371254 sequences. (Running on oeis4.)