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Primes that occur as p - (digit product of p) for p in A228139.
1

%I #9 May 21 2021 08:05:48

%S 11,17,19,31,37,59,113,173,179,193,199,211,227,233,239,241,257,263,

%T 307,311,317,331,383,389,397,419,439,479,499,521,547,563,571,577,613,

%U 617,659,691,719,733,1117,1153,1171,1193,1201,1213,1279,1319,1399,1447,1483,1493,1511,1531,1543,1609,1871

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

%C Terms are unique and in numerical order.

%C There are terms that correspond to more than one member of A228139, such as 17 = 23-2*3 = 89-8*9.

%H Robert Israel, <a href="/A344477/b344477.txt">Table of n, a(n) for n = 1..10000</a>

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

%p d:= 4: # to get terms with at most d digits

%p M:= 10^d + 9^d:

%p f:= proc(n) local L,v;

%p L:= convert(n,base,10);

%p if member(0,L) then return NULL fi;

%p if isprime(n) then

%p v:= n - convert(L,`*`);

%p if isprime(v) then v fi

%p fi

%p end proc:

%p sort(convert(select(`<`,map(f, {seq(i,i=11..M,2)}),10^d),list));

%Y Cf. A228139, A344466.

%K nonn,base

%O 1,1

%A _J. M. Bergot_ and _Robert Israel_, May 20 2021