A077066 Squarefree kernel of prime(n) + 1.

3, 2, 6, 2, 6, 14, 6, 10, 6, 30, 2, 38, 42, 22, 6, 6, 30, 62, 34, 6, 74, 10, 42, 30, 14, 102, 26, 6, 110, 114, 2, 66, 138, 70, 30, 38, 158, 82, 42, 174, 30, 182, 6, 194, 66, 10, 106, 14, 114, 230, 78, 30, 22, 42, 258, 66, 30, 34, 278, 282, 142, 42, 154, 78, 314, 318, 166

Offset: 1

Author

Reinhard Zumkeller, Oct 23 2002

Keywords

• nonn
• easy

Examples

			a(25) = rad(prime(25)+1) = rad(97+1) = rad(2*7^2) = 14.
		

Links

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

Crossrefs

Cf. A007947, A008864, A077063, A077067.

Programs

Haskell

a077066 = a007947 . a008864  -- Reinhard Zumkeller, Sep 04 2013

Mathematica

a[n_] := Times @@ FactorInteger[Prime[n] + 1][[;;, 1]]; Array[a, 100] (* Amiram Eldar, Apr 10 2025 *)

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(A008864(n)).

a(A077067(n)) = A077067(n).