A085051 Smallest multiple of n sandwiched between two numbers both having square divisors.

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

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