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A085050 Smallest multiple of n sandwiched between two squarefree numbers. 1
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 (list; graph; refs; listen; history; text; internal format)
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: A309694 A325263 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

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Last modified July 29 13:28 EDT 2021. Contains 346346 sequences. (Running on oeis4.)