A085050 Smallest multiple of n sandwiched between two squarefree numbers.

2, 2, 6, 4, 20, 6, 14, 16, 18, 20, 22, 12, 52, 14, 30, 16, 34, 18, 38, 20, 42, 22, 92, 72, 150, 52, 54, 56, 58, 30, 186, 32, 66, 34, 70, 36, 222, 38, 78, 40, 164, 42, 86, 88, 90, 92, 94, 96, 196, 150, 102, 52, 106, 54, 110, 56, 114, 58, 236, 60, 366, 186, 252, 128, 130, 66

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Mathematica

PrimeExponents[n_] := Flatten[ Table[ # [[2]], {1}] & /@ FactorInteger[n]]; f[n_] := Block[{k = 1}, While[ Union[ PrimeExponents[k*n - 1]] != {1} || Union[ PrimeExponents[k*n + 1]] != {1}, k++ ]; k*n]; Table[ f[n], {n, 2, 70}]
smn[n_]:=Module[{c=1}, While[!SquareFreeQ[c*n-1]||!SquareFreeQ[c*n+1], c++]; c*n]; Array[smn, 70] (* Harvey P. Dale, Mar 24 2021 *)

Crossrefs

Cf. A005117.

Sequence in context: A325263 A365380 A005992 * A329249 A067045 A083467

Adjacent sequences: A085047 A085048 A085049 * A085051 A085052 A085053

Keyword

easy,nonn

Author

Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jun 20 2003

Extensions

Edited and extended by Robert G. Wilson v, Jun 27 2003

a(1)-a(2) corrected by Amiram Eldar, Feb 24 2021

Status

approved