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
Keywords
Examples
A190641(4) = 12, 12 = 2*2*3, so 12 has only one square factor, namely 4, and the square root is 2.
Links
- Robert Price, Table of n, a(n) for n = 1..10000
Programs
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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 *) -
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