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.

A109959 Numbers n such that concatenating n and the sum of primes dividing n (counting multiplicity) produces a prime.

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%I A109959 #5 Dec 15 2017 17:36:56
%S A109959 10,12,14,22,38,82,90,92,96,116,117,122,134,147,158,165,178,198,210,
%T A109959 218,236,262,274,304,314,332,333,352,358,360,369,387,390,399,420,448,
%U A109959 454,478,482,496,522,561,562,603,605,622,637,639,640,651,694,704,714,720
%N A109959 Numbers n such that concatenating n and the sum of primes dividing n (counting multiplicity) produces a prime.
%C A109959 7^50+144 generates a 62 digit prime.
%H A109959 Harvey P. Dale, <a href="/A109959/b109959.txt">Table of n, a(n) for n = 1..1000</a>
%e A109959 a(5)=38 because 38=2*19 and 19+2=21 and 3821 is prime.
%t A109959 Select[Range[2,1000],PrimeQ[FromDigits[Join[IntegerDigits[#], IntegerDigits[ Total[Times@@@FactorInteger[#]]]]]]&] (* _Harvey P. Dale_, Aug 10 2012 *)
%Y A109959 Cf. A001414, A109958.
%K A109959 easy,nonn,base
%O A109959 1,1
%A A109959 _Jason Earls_, Jul 06 2005