A272141 Numbers such that the concatenation of their aliquot parts, in ascending order, are prime numbers.

9, 14, 21, 26, 27, 34, 35, 46, 49, 55, 57, 58, 62, 74, 98, 115, 118, 143, 155, 158, 161, 166, 169, 178, 183, 187, 194, 201, 202, 209, 214, 215, 218, 219, 221, 226, 245, 265, 279, 287, 295, 298, 309, 314, 323, 326, 327, 329, 335, 341, 355, 371, 374, 377, 381

Offset: 1

Author

Paolo P. Lava, Apr 21 2016

Keywords

• nonn
• base
• easy

Examples

			Aliquot parts of 9 are 1, 3 and concat(1,3) = 13 is prime;
aliquot parts of 3127 are 1, 53, 59 and concat(1,53,59) = 15359 is prime.
		

Links

• Paolo P. Lava, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A176553, A272142.

Programs

Maple

with(numtheory): P:= proc(q) local a,b,k,n;
for n from 1 to q do a:=sort([op(divisors(n))]); b:=0;
for k from 1 to nops(a)-1 do b:=b*10^(ilog10(a[k])+1)+a[k]; od;
if isprime(b) then print(n); fi; od; end: P(10^9);

Mathematica

Select[Range@ 384, PrimeQ@ FromDigits@ Flatten@ IntegerDigits@ Most@ Divisors@ # &] (* Michael De Vlieger, Apr 21 2016 *)