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.

A228139 Primes such that the product of their digits subtracted from the prime number is another prime.

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%I A228139 #12 Jul 29 2017 10:13:59
%S A228139 23,29,41,43,47,83,89,127,149,181,223,227,229,241,251,263,271,277,293,
%T A228139 347,349,367,383,389,419,431,433,439,457,479,487,541,587,631,641,643,
%U A228139 647,653,659,673,677,743,761,853,857,859,863,883,887,1123,1229,1279,1297,1423,1459,1489,1523
%N A228139 Primes such that the product of their digits subtracted from the prime number is another prime.
%H A228139 Paolo P. Lava, <a href="/A228139/b228139.txt">Table of n, a(n) for n = 1..1000</a>
%e A228139 23 is a member since 23-(2*3)=17. 29 is a member since 29-(2*9)=11.
%t A228139 pdsQ[n_]:=Module[{pr=Times@@IntegerDigits[n]},pr!=0&&PrimeQ[n-pr]]; Select[Prime[Range[300]],pdsQ] (* _Harvey P. Dale_, Jul 29 2017 *)
%o A228139 (PARI) dprod(n)=my(v=digits(n));prod(i=1,#v,v[i])
%o A228139 is(n)=my(d=dprod(n)); d>0 && isprime(n) && isprime(n-d) \\ _Charles R Greathouse IV_, Aug 12 2013
%Y A228139 Subsequence of A038618.
%K A228139 nonn,base
%O A228139 1,1
%A A228139 _Will Gosnell_, Aug 12 2013
%E A228139 a(3), a(10), a(15)-a(57) from _Charles R Greathouse IV_, Aug 12 2013