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#85 by Michel Marcus at Fri Sep 09 02:33:47 EDT 2022
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#84 by Joerg Arndt at Fri Sep 09 01:42:59 EDT 2022
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#83 by Chai Wah Wu at Thu Sep 08 23:23:11 EDT 2022
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#82 by Chai Wah Wu at Thu Sep 08 23:22:42 EDT 2022
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| PROG
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from math import prod
from sympy.solvers.diophantine.diophantine import diop_DNfactorint
def A000161(n):
f = factorint(n)
def return int(not A000161any(n): returne&1 for e in lenf.values())) + (((m:=prod(diop_DN(-1 if p==2 else (e+1 if p&3==1 else (e+1)&1, ) for p, e in f.items()))+((((~n & n))>>-1).bit_length()&1)<<1)-1 if m&1 else 0))>>1) if n else 1 # Chai Wah Wu, Sep 08 2022
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#81 by Chai Wah Wu at Thu Sep 08 23:12:19 EDT 2022
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(Python)
from sympy.solvers.diophantine.diophantine import diop_DN
def A000161(n): return len(diop_DN(-1, n))>>1 if n else 1 # Chai Wah Wu, Sep 08 2022
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| STATUS
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approved
editing
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#80 by Alois P. Heinz at Tue Apr 12 08:19:56 EDT 2022
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#79 by Bernard Schott at Tue Apr 12 07:22:45 EDT 2022
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#78 by Bernard Schott at Tue Apr 12 07:21:48 EDT 2022
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Discussion
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| Tue Apr 12
| 07:22
| Bernard Schott: Deleted, was in comment, sorry.
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#77 by Bernard Schott at Tue Apr 12 07:21:02 EDT 2022
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#76 by Bernard Schott at Tue Apr 12 07:20:26 EDT 2022
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Discussion
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| Tue Apr 12
| 07:20
| Bernard Schott: Put iff for a(n) = 0.
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