A133295 Smallest squarefree k such that the first n nonzero values of mu(j), j>=k, are all equal (mu is the Moebius function).

1, 2, 2, 91, 97, 201, 201, 598, 2683, 2683, 2683, 3090, 3090, 38401, 38401, 41226, 293037, 293037, 294574, 2156849, 4819826, 8812154, 10309514, 10309514, 10309514, 39479386, 476531349, 768912879, 1654065545, 5332819918, 8974545041, 16907435569, 17785220641

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..37

Example

a(6)=201 because the first occurrence of 6 consecutive squarefree numbers with numbers of prime divisors having the same parity is 201, 202, 203, 205, 206, 209.

Mathematica

f[n_] := Module[{c = 0, m = MoebiusMu[n]}, If[m == 0, Return[0]]; nn = n; mm = m; While[mm == 0 || mm == m, If[mm != 0, c++]; nn++; mm = MoebiusMu[nn]]; c]; mx = 19; v = Table[0, {mx}]; count = 0; Do[f1 = f[n]; Do[If[v[[j]] == 0, v[[j]] = n; count++], {j, 1, f1}]; If[count == mx, Break[]], {n, 1, 10^6}]; v (* Amiram Eldar, Aug 30 2019 *)

Crossrefs

Cf. A005117, A008683.

Sequence in context: A191779 A156511 A166996 * A055470 A270591 A210467

Adjacent sequences: A133292 A133293 A133294 * A133296 A133297 A133298

Keyword

nonn

Author

Michel Balazard (balazard(AT)math.u-bordeaux1.fr), Oct 17 2007, Oct 19 2007

Extensions

More terms from Amiram Eldar, Aug 30 2019

Status

approved