A380470 Numbers k that are squarefree, but A380459(k) is not in A048103.

10, 15, 21, 22, 30, 33, 34, 35, 39, 42, 46, 51, 55, 57, 58, 65, 66, 69, 70, 77, 78, 82, 85, 87, 91, 93, 94, 95, 102, 105, 106, 110, 111, 114, 115, 118, 119, 123, 129, 130, 133, 138, 141, 142, 143, 145, 154, 155, 159, 161, 165, 166, 170, 174, 177, 178, 182, 183, 185, 187, 190, 195, 201, 202, 203, 205, 209, 210, 213

Offset

1,1

Comments

See also comments in A380530.

Links

Antti Karttunen, Table of n, a(n) for n = 1..20000

Example

From Antti Karttunen, May 09 2025: (Start)
10 = 2*5 is a term, as it is squarefree, and A380459(10) = 54 = 2 * 3^3, thus the prime factor 3 overflows, i.e., has an exponent at least as large as that prime.
5117046 = 2*3*11*31*41*61 is a term, as it is squarefree, and A380459(5117046) = 2 * 3^2 * 5^4 * 7^11 * 11^22 * 13^36 * 17^31 * 19^8, thus the least prime factor which overflows is 7 [= A380528(5117046)].
31203546 = 2*3*11*31*101*151 is a term, as it is squarefree, and A380459(31203546) = 2 * 3^2 * 5^4 * 7^6 * 11^28 * 13^37 * 17^56 * 19^18 * 23^2, thus the least prime factor which overflows is 11 [= A380528(31203546)].
(End)

Prog

(PARI) is_A380470 = A380469;

Crossrefs

Setwise difference A005117 \ A380468.

Cf. A380469 (characteristic function), A380528, A380530.

Sequence in context: A105156 A108614 A336548 * A115708 A068992 A325901

Adjacent sequences: A380467 A380468 A380469 * A380471 A380472 A380473

Keyword

nonn

Author

Antti Karttunen, Feb 02 2025

Status

approved