OFFSET
1,2
COMMENTS
Essentially the same as A061228. [R. J. Mathar, Apr 16 2009]
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..10000
FORMULA
If n = Product (p_i^e_i), where p_1 < p_2 < ... < p_k, a(n) = n + p_1. For p = primes (A000040), a(p) = 2*p.
a(n) = n + A020639(n), for n > 1. - Michel Marcus, Dec 02 2018
MATHEMATICA
f[n_]:= n + FactorInteger[n][[1, 1]]; Join[{1}, Array[f, 70, 2]] (* Vincenzo Librandi, Dec 02 2018 *)
PROG
(PARI) a(n) = if (n==1, 1, n+factor(n)[1, 1]); \\ Michel Marcus, Dec 02 2018
(Magma) [1] cat [n + PrimeDivisors(n)[1]: n in [2..100]]; // Vincenzo Librandi, Dec 02 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Apr 13 2009
EXTENSIONS
More terms from Michel Marcus, Dec 02 2018
STATUS
approved