cp's OEIS Frontend

A134873 Primes p with the property that the sum of the digits of the product of the digits of p is also a prime number.

%I A134873 #11 Jan 16 2019 11:13:09
%S A134873 2,3,5,7,13,17,31,37,43,71,73,113,127,131,137,151,173,211,223,257,271,
%T A134873 277,281,311,317,431,457,523,541,547,557,577,727,757,821,853,1117,
%U A134873 1151,1171,1187,1217,1223,1277,1427,1451,1481,1511,1523
%N A134873 Primes p with the property that the sum of the digits of the product of the digits of p is also a prime number.
%H A134873 Erich Leistenschneider, <a href="/A134873/b134873.txt">Table of n, a(n) for n = 1..4095</a>
%H A134873 Erich Lestenschneider's <a href="http://www.erichl.net/?a=13">Article</a> about this sequence (in Portuguese).
%H A134873 Erich Leistenschneider, <a href="http://www.erichl.net/arq/sequence">Program used to generate the sequence (Linux)</a>
%H A134873 Erich Leistenschneider, <a href="http://www.erichl.net/arq/seq.txt">First 4095 numbers of the sequence</a>
%e A134873 2531 is a member of this sequence because it is a prime number and the product of its digits is 2*5*3*1 = 30 and the sum of the digits of this result is 3+0 = 3, which is also a prime number.
%p A134873 a:=proc(n) local dn,pr,dpr: dn:=convert(n,base,10): pr:=mul(dn[i],i=1..nops(dn)): dpr:=convert(pr,base,10): if isprime(n)=true and isprime(add(dpr[j],j= 1..nops(dpr)))=true then n else end if end proc: seq(a(n),n=1..1600); # _Emeric Deutsch_, Mar 01 2008
%t A134873 Select[Prime[Range[300]],PrimeQ[Total[IntegerDigits[Times@@ IntegerDigits[#]]]]&] (* _Harvey P. Dale_, Dec 15 2011 *)
%o A134873 (PARI) isok(p) = isprime(p) && isprime(sumdigits(vecprod(digits(p)))); \\ _Michel Marcus_, Jan 16 2019
%Y A134873 Subsequence of A038618 (zeroless primes).
%K A134873 nonn,base
%O A134873 1,1
%A A134873 Erich Leistenschneider (el(AT)erichl.net), Feb 01 2008