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A074174
Smallest number k such that k and k+n are of the form p^2*q where p and q are primes.
4
44, 18, 172, 171, 45, 12, 45, 12, 236, 18, 52, 63, 50, 261, 524, 12, 28, 45, 44, 637, 404, 28, 45, 20, 20, 18, 18, 147, 63, 20, 44, 12, 12, 18, 28, 63, 116, 12, 236, 12, 75, 50, 20, 325, 18, 52, 28, 20, 50, 18, 12, 423, 45, 44, 20, 12, 18, 18, 116, 147, 63, 325, 12, 12, 52
OFFSET
1,1
LINKS
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