A304181 If n = Product (p_j^k_j) then a(n) = min{p_j}^min{k_j}.

1, 2, 3, 4, 5, 2, 7, 8, 9, 2, 11, 2, 13, 2, 3, 16, 17, 2, 19, 2, 3, 2, 23, 2, 25, 2, 27, 2, 29, 2, 31, 32, 3, 2, 5, 4, 37, 2, 3, 2, 41, 2, 43, 2, 3, 2, 47, 2, 49, 2, 3, 2, 53, 2, 5, 2, 3, 2, 59, 2, 61, 2, 3, 64, 5, 2, 67, 2, 3, 2, 71, 4, 73, 2, 3, 2, 7, 2, 79, 2, 81, 2, 83, 2, 5

Offset: 1

Author

Ilya Gutkovskiy, May 07 2018

Keywords

• nonn

Examples

			a(72) = 4 because 72 = 2^3*3^2, min{2,3} = 2, min{3,2} = 2 and 2^2 = 4.
		

Links

• Eric Weisstein's World of Mathematics, Least Prime Factor
• Index entries for sequences computed from exponents in factorization of n

Crossrefs

Cf. A000040, A000961 (fixed points), A005117, A020639, A028233, A034684, A051904, A073481, A081811, A304180.

Programs

Mathematica

Table[(FactorInteger[n][[1, 1]])^(Min @@ Last /@ FactorInteger[n]), {n, 85}]

Formula

a(n) = A020639(n)^A051904(n).

a(p^k) = p^k where p is a prime.

a(A005117(k)) = A073481(k).