Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #15 Mar 24 2021 17:42:51
%S 2,2,6,4,20,6,14,16,18,20,22,12,52,14,30,16,34,18,38,20,42,22,92,72,
%T 150,52,54,56,58,30,186,32,66,34,70,36,222,38,78,40,164,42,86,88,90,
%U 92,94,96,196,150,102,52,106,54,110,56,114,58,236,60,366,186,252,128,130,66
%N Smallest multiple of n sandwiched between two squarefree numbers.
%H Amiram Eldar, <a href="/A085050/b085050.txt">Table of n, a(n) for n = 1..10000</a>
%t 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}]
%t 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 *)
%Y Cf. A005117.
%K easy,nonn
%O 1,1
%A _Amarnath Murthy_ and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jun 20 2003
%E Edited and extended by _Robert G. Wilson v_, Jun 27 2003
%E a(1)-a(2) corrected by _Amiram Eldar_, Feb 24 2021