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A088611
a(1) = 1, a(n) = n-th squarefree number if n is squarefree else a(n) is the n-th nonsquarefree number.
2
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
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
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Oct 16 2003
EXTENSIONS
Corrected and extended by Ray Chandler, Oct 18 2003
STATUS
approved