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A090093
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a(n) is the smallest composite number coprime to n, n+1, n+2, n+3.
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4
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25, 49, 49, 121, 121, 25, 121, 49, 49, 49, 25, 121, 121, 121, 49, 25, 49, 121, 169, 169, 25, 49, 49, 49, 121, 25, 121, 121, 49, 49, 25, 169, 169, 121, 121, 25, 49, 49, 121, 121, 25, 169, 49, 49, 49, 25, 121, 121, 121, 49, 25, 49, 169, 169, 169, 25, 49, 49, 49, 121, 25
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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FORMULA
| a(n)=A053672[n]^2
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MATHEMATICA
| m=0; Table[fla=1; Do[s=GCD[n, k]; s1=GCD[n, k+1]; s2=GCD[n, k+2]; s3=GCD[n, k+3]; If[Equal[s, 1]&&Equal[s1, 1] &&Equal[s2, 1]&&Equal[s3, 1]&&!PrimeQ[n]&&!Equal[n, 1] &&Equal[fla, 1], m=m+1; Print[n]; fla=0], {n, 1, 1000}], {k, 1, 256}]
With[{compnos=Complement[Range[2, 500], Prime[Range[PrimePi[500]]]]}, Table[ First[Select[compnos, And@@CoprimeQ[#, n+Range[0, 3]]&]], {n, 70}]] (* From Harvey P. Dale, Aug 10 2011 *)
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CROSSREFS
| Cf. A053669-A053674, A090090-A090093.
Sequence in context: A154082 A143278 A106632 * A004936 A062058 A198591
Adjacent sequences: A090090 A090091 A090092 * A090094 A090095 A090096
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KEYWORD
| nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Nov 26 2003
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