cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A283598 Numbers k such that all three of 6*k+1, 6*(k+1)+1, and 6*(k+2)+1 are semiprimes.

Original entry on oeis.org

41, 42, 48, 84, 92, 148, 157, 158, 162, 189, 209, 210, 222, 223, 224, 225, 226, 234, 250, 306, 315, 316, 317, 318, 319, 326, 386, 387, 401, 407, 408, 433, 462, 487, 488, 489, 514, 515, 521, 532, 539, 566, 567, 568, 569, 580, 598, 633, 634, 662, 663, 664, 672, 697, 713, 717, 718
Offset: 1

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Author

Zak Seidov, Mar 14 2017

Keywords

Comments

That is, k, k+1 and k+2 are terms in A112775.

Crossrefs

Subsequence of A283597 and A112775.

Programs

  • Mathematica
    po[x_]=PrimeOmega[x];Select[Range[1000],po[6*#+1]==po[6*(1+#)+1]==po[6*(2+#)+1]==2 &]
    Select[Range[800],PrimeOmega[6#+{1,7,13}]=={2,2,2}&] (* Harvey P. Dale, Apr 23 2024 *)
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