OFFSET
1
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..100000
Jon Maiga, Computer-generated formulas for A359549, Sequence Machine.
FORMULA
MATHEMATICA
a[n_] := If[(e = IntegerExponent[n, 2]) < 2 && SquareFreeQ[Sqrt[n/2^e]], 1, 0] ; Array[a, 100] (* Amiram Eldar, Jan 07 2023 *)
PROG
(PARI) A359549(n) = { my(f=factor(n)); prod(k=1, #f~, if(2==f[k, 1], (1==f[k, 2]), (2==f[k, 2]))); };
(Python)
from sympy import factorint
def A359549(n): return int((m:=(~n & n-1).bit_length())<2 and all(e==2 for e in factorint(n>>m).values())) # Chai Wah Wu, Jan 11 2023
KEYWORD
nonn,mult
AUTHOR
Antti Karttunen, Jan 06 2023
STATUS
approved