OFFSET
1,2
COMMENTS
This sequence has similarities with A087019.
These are the positions of first appearances of each positive integer in A346701, and also in A346703. - Gus Wiseman, Aug 09 2021
LINKS
FORMULA
a(n) = n iff n = 1 or n is a prime number.
a(p^k) = p^(2*k-1) for any k > 0 and any prime number p.
From Gus Wiseman, Aug 09 2021: (Start)
If g = A006530(n) is the greatest prime factor of n, then a(n) = n^2/g.
a(n) = A129597(n)/2.
(End)
EXAMPLE
For n = 42:
- 42 = 2 * 3 * 7, so:
2 3 7
x 2 3 7
-------
2 3 7
2 3 3
+ 2 2 2
-----------
2 2 3 3 7
- hence a(42) = 2 * 2 * 3 * 3 * 7 = 252.
MATHEMATICA
Table[n^2/FactorInteger[n][[-1, 1]], {n, 100}] (* Gus Wiseman, Aug 09 2021 *)
PROG
(PARI) See Links section.
CROSSREFS
KEYWORD
nonn
AUTHOR
Rémy Sigrist, Apr 02 2021
STATUS
approved