A188525 a(n) = rad(rad(n)^2+1), where rad = A007947.

2, 5, 10, 5, 26, 37, 10, 5, 10, 101, 122, 37, 170, 197, 226, 5, 290, 37, 362, 101, 442, 485, 530, 37, 26, 677, 10, 197, 842, 901, 962, 5, 1090, 1157, 1226, 37, 1370, 85, 1522, 101, 58, 1765, 370, 485, 226, 2117, 2210, 37, 10, 101, 2602, 677, 2810, 37

Offset

1,1

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Formula

a(n) = A007947(A078615(n)+1). - R. J. Mathar, Apr 04 2011

Example

a(7) = rad(rad(7)^2 + 1) = rad(7^2 + 1) = rad(50) = 10.

Maple

with(numtheory):
rad:= n-> mul(i, i=factorset(n)):
a:= n-> rad(rad(n)^2+1):
seq(a(n), n=1..70);  # Alois P. Heinz, Apr 03 2011

Mathematica

rad[n_] := Times @@ FactorInteger[n][[All, 1]];
a[n_] := rad[rad[n]^2 + 1];
Array[a, 70] (* Jean-François Alcover, Mar 27 2017 *)

Prog

(Magma) [ &*PrimeDivisors((&*PrimeDivisors(n))^2+1): n in [1..51] ]; // Bruno Berselli, Apr 04 2011
(PARI) rad(n)=my(f=factor(n)[, 1]); prod(i=1, #f, f[i])
a(n)=rad(rad(n)^2+1) \\ Charles R Greathouse IV, Aug 08 2013

Crossrefs

Cf. A007947, A078322.

Sequence in context: A224300 A175467 A361806 * A324503 A126842 A291933

Adjacent sequences: A188522 A188523 A188524 * A188526 A188527 A188528

Keyword

nonn,easy

Author

Jonathan Vos Post, Apr 03 2011

Status

approved