A109958 - OEIS

%I #13 Apr 20 2024 00:03:56

%S 10,22,33,44,55,65,77,86,96,107,1111,127,1313,149,158,168,1717,188,

%T 1919,209,2110,2213,2323,249,2510,2615,279,2811,2929,3010,3131,3210,

%U 3314,3419,3512,3610,3737,3821,3916,4011,4141,4212,4343,4415,4511,4625,4747

%N Concatenate n and the sum of primes dividing n (counting multiplicity).

%H Robert Israel, <a href="/A109958/b109958.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = 10^(A055652(A001414(n)))*n+A001414(n). - _Robert Israel_, Jun 26 2018

%p f:= proc(n) local q;

%p q:= add(t[1]*t[2],t=ifactors(n)[2]);

%p 10^(1+ilog10(q))*n+q

%p end proc:

%p f(1):= 10:

%p map(f, [$1..100]); # _Robert Israel_, Jun 26 2018

%t pr[{a_,b_}]:=a*b;Join[{10},Table[FromDigits[Flatten[IntegerDigits[Join[{n},{Total[pr/@FactorInteger[n]]}]]]],{n,2,47}]] (* _James C. McMahon_, Apr 02 2024 *)

%Y Cf. A001414, A055652, A109959.

%K easy,nonn,base

%O 1,1

%A _Jason Earls_, Jul 06 2005