A088611 a(1) = 1, a(n) = n-th squarefree number if n is squarefree else a(n) is the n-th nonsquarefree number.

1, 2, 3, 12, 6, 7, 10, 24, 25, 14, 15, 32, 19, 21, 22, 45, 26, 49, 30, 52, 33, 34, 35, 63, 64, 39, 72, 75, 43, 46, 47, 84, 53, 55, 57, 96, 59, 61, 62, 104, 66, 67, 69, 117, 120, 73, 74, 125, 126, 128, 82, 135, 85, 140, 87, 147, 91, 93, 94, 153, 97, 101, 162, 164, 105, 106

Offset

1,2

Links

Table of n, a(n) for n=1..66.

Example

a(4) = 12, the 4th nonsquarefree number.

Prog

(Python)
# uses programs from A005117 and A013929
from sympy import factorint
def A088611(n): return A005117(n) if max(factorint(n).values(), default=0)<2 else A013929(n) # Chai Wah Wu, Aug 12 2024

Crossrefs

Cf. A088612, A005117, A013929.

Sequence in context: A056819 A124442 A220271 * A361323 A292265 A259416

Adjacent sequences: A088608 A088609 A088610 * A088612 A088613 A088614

Keyword

nonn

Author

Amarnath Murthy, Oct 16 2003

Extensions

Corrected and extended by Ray Chandler, Oct 18 2003

Status

approved