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.

A082883 Primes p(x) satisfying the following conditions: [1]# A082882(x)=1; [2]# {p(x),p(x+1)} are not twin primes; [3]# values of A075860(j) for j composites between these two non-twin primes are identical. See also A075860, A082880-A082882.

Original entry on oeis.org

103, 457, 1009, 1663, 2953, 3079, 6043, 12007, 17707, 20749, 21499, 25579, 28537, 30703, 41227, 54367, 55663, 59443, 66973, 70309, 81547, 83557, 90019, 97003, 101359, 102559, 105367, 108499, 116239, 120847, 126019, 129733, 133873, 138403
Offset: 1

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Author

Labos Elemer, Apr 16 2003

Keywords

Examples

			p[2033]=17007 is here because next prime is 17013;
for the five j inter-prime composites
i.e. if j is from {17008,..,17012} the values
of A075860 are identical: {7,7,7,7,7}, so A082882(2033)=1;
Smallest such example is a(1)=103 with this sophisticated
property:for i={104,105,106} the fixed points of A008472(i)
i.e. values of A075860(i) are uniformly equal to 2.
		

Crossrefs

Programs

  • Mathematica
    ffi[x_] := Flatten[FactorInteger[x]] lf[x_] := Length[FactorInteger[x]] ba[x_] := Table[Part[ffi[x], 2*w-1], {w, 1, lf[x]}] sopf[x_] := Apply[Plus, ba[x]] Do[s=Length[Union[tik=Table[FixedPoint[sopf, j], {j, 1+Prime[n], -1+Prime[n+1]}]]]; If[Equal[s, 1]&&!PrimeQ[2+Prime[n]], Print[Prime[n]]], {n, 1, 100000}]