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.

A225303 Primes of the form p + (product of digits of p), where p is a prime.

Original entry on oeis.org

29, 47, 67, 101, 103, 107, 109, 181, 251, 293, 307, 331, 347, 401, 409, 431, 443, 457, 491, 503, 509, 547, 593, 601, 607, 631, 653, 659, 673, 701, 709, 743, 809, 823, 827, 839, 907, 929, 971, 977, 1009, 1013, 1019, 1021, 1031, 1033, 1039, 1049, 1051, 1061, 1063, 1069, 1087, 1091
Offset: 1

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Author

Jayanta Basu, May 05 2013

Keywords

Comments

Primes generated by A157677.

Examples

			29 is in the list since 29 = 23 + (2*3).
		

Crossrefs

Cf. A157677.

Programs

  • Maple
    f:= proc(n) local L,v;
      if not isprime(n) then return NULL fi;
      L:= convert(n,base,10);
      if member(0,L) then return n fi;
      v:= n + convert(L,`*`);
      if isprime(v) then v else NULL fi
    end proc:
    N:= 2000: # to get all terms <= N
    S:= {}:
    for n from 3 by 2 to N do
      v:= f(n);
      if v <> NULL and v <= N then S:= S union {v} fi;
    od:
    sort(convert(S,list));# Robert Israel, Jun 25 2019
  • Mathematica
    Sort[DeleteDuplicates[Select[Table[p=Prime[n]; p+Times@@IntegerDigits[p], {n,175}],PrimeQ]]]
    Select[Table[p+Times@@IntegerDigits[p],{p,Prime[Range[ 200]]}], PrimeQ]// Union (* Harvey P. Dale, Sep 21 2019 *)

Extensions

1049,1051,1061,1063,1069 and 1087 inserted by Robert Israel, Jun 25 2019