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.

A288340 a(n) is the smallest prime that is the sum of both 2n-1 and 2n+1 consecutive primes.

Original entry on oeis.org

23, 83, 311, 401, 1367, 3617, 863, 5683, 1523, 153113, 90011, 10949, 7901, 155671, 11131, 117977, 14699, 252079, 58369, 132749, 203293, 641867, 116257, 607093, 78791, 46471, 927049, 340601, 1485541, 521897, 99149, 771889, 2153993, 227869, 2349251, 4762213, 56099, 3232093, 944003, 1006781
Offset: 1

Views

Author

Robert G. Wilson v, Jun 08 2017

Keywords

Comments

Inspired by A213174.
Records: 23, 83, 311, 401, 1367, 3617, 5683, 153113, 155671, 252079, 641867, 927049, 1485541, 2153993, 2349251, 4762213, ..., . - Robert G. Wilson v, Jun 11 2017

Crossrefs

Cf. A213174.

Programs

  • Mathematica
    pr = Prime@ Range@ 25000; f[n_] := Select[ Intersection[Plus @@@ Partition[pr, 2n -1, 1], Plus @@@ Partition[pr, 2n +1, 1]], PrimeQ][[1]]; Array[f, 40] (* or *)
    f[n_] := Block[{a = Prime@ Range[2, 2n], p = Prime[2n +1], b = Prime@ Range[2, 2n +2], q = Prime[2n +3]}, While[aa = Plus @@ a; bb = Plus @@ b; aa != bb || ! PrimeQ@ aa, If[aa < bb, a = Join[Rest@ a, {p}]; p = NextPrime@ p, b = Join[Rest@ b, {q}]; q = NextPrime@ q]]; Plus @@ a]; Array[f, 40]