A283671 Square root of the single square referenced in A190641.

2, 2, 3, 2, 2, 3, 2, 2, 5, 3, 2, 2, 2, 2, 3, 2, 7, 5, 2, 3, 2, 2, 3, 2, 2, 5, 2, 2, 3, 2, 2, 3, 2, 2, 7, 3, 2, 2, 2, 3, 2, 11, 2, 5, 3, 2, 2, 3, 2, 2, 7, 2, 5, 2, 3, 2, 2, 3, 2, 2, 13, 3, 2, 5, 2, 2, 2, 3, 2, 3, 2, 3, 2, 2, 2, 2, 2, 2, 3, 2, 2, 11, 3, 2, 7

Offset

1,1

Links

Robert Price, Table of n, a(n) for n = 1..10000

Formula

a(n) = sqrt(A283670(n)) = A249739(A190641(n)). - Amiram Eldar, Jul 28 2024

Example

A190641(4) = 12, 12 = 2*2*3, so 12 has only one square factor, namely 4, and the square root is 2.

Mathematica

f[n_] := Module[{f = FactorInteger[n], ind}, ind = Position[f[[;; , 2]], _?(# > 1 &)]; If[Length[ind] == 1, f[[ind[[1, 1]], 1]], Nothing]]; Array[f, 300] (* Amiram Eldar, Jul 28 2024 *)

Prog

(PARI) lista(kmax) = for(k = 1, kmax, my(f = factor(k)); if(#select(x -> (x>1), f[, 2]) == 1, for(i = 1, #f~, if(f[i, 2] > 1, print1(f[i, 1], ", "); break)))); \\ Amiram Eldar, Jul 28 2024

Crossrefs

Cf. A190641, A249739, A283670.

Sequence in context: A130451 A130285 A046027 * A046028 A330406 A125954

Adjacent sequences: A283668 A283669 A283670 * A283672 A283673 A283674

Keyword

nonn

Author

Robert Price, Mar 13 2017

Status

approved