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A378540
a(n) = 1 if n is a practical number (A005153) that is neither a square or twice a square, otherwise a(n) = 0.
2
0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0
OFFSET
1
FORMULA
a(n) = (1-A053866(n)) * A322860(n).
a(n) <= A179527(n).
PROG
(PARI) A378540(n) = (!(sigma(n)%2) && is_A005153(n));
CROSSREFS
Characteristic function of A378541.
Differs from A179527 on n given by A353061.
Sequence in context: A378449 A286925 A378598 * A179527 A353528 A358755
KEYWORD
nonn,new
AUTHOR
Antti Karttunen, Dec 02 2024
STATUS
approved