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A085051 Smallest multiple of n sandwiched between two numbers both having square divisors. 1
17, 26, 51, 244, 55, 846, 49, 424, 99, 170, 55, 3480, 26, 476, 1275, 1376, 17, 846, 19, 1520, 651, 638, 161, 3480, 125, 26, 243, 476, 377, 3480, 341, 1376, 99, 170, 595, 6876, 629, 874, 351, 1520, 451, 28224, 559, 2024, 1665, 874, 235, 18768, 49, 7300, 51, 5824 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

a(7) = 49 as 48 (= 4^2*3) and 50 (= 5^2*2 ) both are divisible by squares.

MATHEMATICA

PrimeExponents[n_] := Last[ Union[ Flatten[ Table[ # [[2]], {1}] & /@ FactorInteger[n]]]]; f[n_] := Block[{k = 1}, While[a = k*n; PrimeExponents[a - 1] < 2 || PrimeExponents[a + 1] < 2, k++ ]; k*n]; Table[ f[n], {n, 1, 52}]

smn[n_]:=Module[{k=1}, While[AnyTrue[k*n+{1, -1}, SquareFreeQ], k++]; k*n]; Array[smn, 60] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 04 2018 *)

CROSSREFS

Sequence in context: A034963 A120143 A031204 * A171954 A336272 A154277

Adjacent sequences:  A085048 A085049 A085050 * A085052 A085053 A085054

KEYWORD

nonn

AUTHOR

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

EXTENSIONS

Edited, corrected and extended by Robert G. Wilson v, Jun 21 2003

STATUS

approved

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Last modified July 26 12:20 EDT 2021. Contains 346294 sequences. (Running on oeis4.)