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.

A337028 Numbers k such that k + A001414(k), k - A001414(k) and k mod A001414(k) are all prime.

Original entry on oeis.org

10, 12, 14, 15, 20, 26, 33, 35, 38, 51, 65, 68, 86, 96, 111, 112, 116, 161, 201, 203, 206, 209, 215, 221, 278, 297, 300, 304, 321, 371, 395, 398, 413, 420, 471, 533, 545, 551, 570, 626, 671, 698, 720, 755, 779, 803, 837, 858, 866, 910, 972, 1020, 1046, 1124, 1155, 1161, 1286, 1326, 1349, 1385
Offset: 1

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Author

J. M. Bergot and Robert Israel, Aug 11 2020

Keywords

Examples

			a(3)=14 is in the sequence because A001414(14)=9, and 14-9=5, 14+9=23 and 14 mod 9 = 5 are all prime.
		

Crossrefs

Cf. A001414. Subset of A050705.

Programs

  • Maple
    A001414:= proc(n) local F; F:= ifactors(n)[2]; convert(map(convert,F,`*`),`+`) end proc:
    filter:= proc(n) local s; s:= A001414(n); isprime(n+s) and isprime(n-s) and isprime(n mod s) end proc:
    select(filter, [$1..2000]);