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A272142 Numbers such that the concatenation of their aliquot parts, in descending order, are prime numbers.

%I A272142 #8 Apr 22 2016 23:48:46
%S A272142 8,9,10,26,34,35,49,55,56,57,62,63,75,76,77,94,95,115,122,125,142,144,
%T A272142 146,161,169,183,194,196,203,206,219,226,235,238,254,262,265,274,275,
%U A272142 278,290,299,302,304,305,309,320,322,332,336,338,346,355,358,361,362
%N A272142 Numbers such that the concatenation of their aliquot parts, in descending order, are prime numbers.
%H A272142 Paolo P. Lava, <a href="/A272142/b272142.txt">Table of n, a(n) for n = 1..10000</a>
%e A272142 Aliquot parts of 8 are 1, 2, 4 and concat(4,2,1) = 421 is prime;
%e A272142 aliquot parts of 1822 are 1, 2, 911 and concat(911,2,1) = 91121 is prime.
%p A272142 with(numtheory): P:= proc(q) local a,b,k,n;
%p A272142 for n from 1 to q do a:=sort([op(divisors(n))]); b:=0;
%p A272142 for k from nops(a)-1 by -1 to 1 do b:=b*10^(ilog10(a[k])+1)+a[k]; od;
%p A272142 if isprime(b) then print(n); fi; od; end: P(10^9);
%t A272142 Select[Range@ 362, PrimeQ@ FromDigits@ Flatten@ IntegerDigits@ Reverse@ Most@ Divisors@ # &] (* _Michael De Vlieger_, Apr 21 2016 *)
%Y A272142 Cf. A176553, A272141.
%K A272142 nonn,base,easy
%O A272142 1,1
%A A272142 _Paolo P. Lava_, Apr 21 2016