OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
a(2) = 18 as 18 = 3^2*2 and 18 +2 =20 = 2^2*5.
MATHEMATICA
Table[k=1; found=False; While[ !found, k++; f1=FactorInteger[k]; If[Sort[Transpose[f1][[2]]]=={1, 2}, f2=FactorInteger[k+n]; If[Sort[Transpose[f2][[2]]]=={1, 2}, found=True]]]; k, {n, 100}]
snk[n_]:=Module[{k=1}, While[Sort[FactorInteger[k][[All, 2]]]!={1, 2} || Sort[FactorInteger[k+n][[All, 2]]]!={1, 2}, k++]; k]; Array[snk, 70]
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Aug 30 2002
EXTENSIONS
Corrected and extended by T. D. Noe, Oct 04 2004
STATUS
approved