A240593 The smaller of a pair of consecutive composite squarefree numbers (A120944) without any prime number between them.
14, 21, 33, 34, 38, 55, 57, 62, 65, 69, 74, 77, 85, 86, 91, 93, 94, 105, 110, 114, 115, 118, 119, 122, 129, 133, 141, 142, 143, 145, 154, 158, 159, 165, 174, 177, 182, 183, 185, 186, 187, 194, 201, 202, 203, 205, 206, 209, 213, 214, 215, 217, 218, 219, 221, 230, 235, 237, 246, 247, 253, 254, 258, 259, 265, 266, 273, 285, 286, 287, 290, 295, 298, 299
Offset: 1
Keywords
Examples
62 is in the sequence because A120944(20)=62, A120944(21)=65, without primes between them.
Programs
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Mathematica
Select[Partition[Select[Range[400],CompositeQ[#]&&SquareFreeQ[#]&],2,1], PrimePi[ #[[1]]]==PrimePi[#[[2]]]&][[All,1]] (* Harvey P. Dale, Apr 12 2020 *)
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PARI
freesqrcomp(n)=issquarefree(n)&&!isprime(n) nextfqc(n)={local(k); k=n+1; while(!freesqrcomp(k), k+=1); return(k)} {for(i=2, 1000, if(freesqrcomp(i) && (nextfqc(i)
Comments