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.

A344477 Primes that occur as p - (digit product of p) for p in A228139.

Original entry on oeis.org

11, 17, 19, 31, 37, 59, 113, 173, 179, 193, 199, 211, 227, 233, 239, 241, 257, 263, 307, 311, 317, 331, 383, 389, 397, 419, 439, 479, 499, 521, 547, 563, 571, 577, 613, 617, 659, 691, 719, 733, 1117, 1153, 1171, 1193, 1201, 1213, 1279, 1319, 1399, 1447, 1483, 1493, 1511, 1531, 1543, 1609, 1871
Offset: 1

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Author

J. M. Bergot and Robert Israel, May 20 2021

Keywords

Comments

Terms are unique and in numerical order.
There are terms that correspond to more than one member of A228139, such as 17 = 23-2*3 = 89-8*9.

Examples

			a(5) = 37 is a term because 41 is prime with no digit 0 and 37 = 41-4*1.
		

Crossrefs

Programs

  • Maple
    d:= 4: # to get terms with at most d digits
    M:= 10^d + 9^d:
    f:= proc(n) local L,v;
      L:= convert(n,base,10);
      if member(0,L) then return NULL fi;
      if isprime(n) then
        v:= n - convert(L,`*`);
        if isprime(v) then v fi
      fi
    end proc:
    sort(convert(select(`<`,map(f, {seq(i,i=11..M,2)}),10^d),list));