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.

A081637 Class 9+ primes.

Original entry on oeis.org

532801, 710341, 720617, 1212487, 1261157, 1372081, 1457293, 1490429, 1532173, 1657801, 1788547, 1789093, 1809601, 1829293, 1887877, 1944181, 1960141, 1997587, 2121853, 2161853, 2474413, 2484049, 2557441, 2578801, 2613607
Offset: 1

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Author

Robert G. Wilson v, Mar 20 2003

Keywords

References

  • R. K. Guy, Unsolved Problems in Number Theory, A18.

Crossrefs

Programs

  • Maple
    For Maple program see Mathar link in A005105.
  • Mathematica
    PrimeFactors[n_Integer] := Flatten[ Table[ #[[1]], {1}] & /@ FactorInteger[n]]; f[n_Integer] := Block[{m = n}, If[m == 0, m = 1, While[ IntegerQ[m/2], m /= 2]; While[ IntegerQ[m/3], m /= 3]]; Apply[Times, PrimeFactors[m] + 1]]; ClassPlusNbr[n_] := Length[ NestWhileList[f, n, UnsameQ, All]] - 3; Prime[ Select[ Range[196000], ClassPlusNbr[ Prime[ # ]] == 9 &]]