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A324659
a(n) = (1/2)*A318468(n), where A318468(n) is bitwise-AND of 2*n and sigma(n).
4
0, 0, 2, 0, 1, 6, 4, 0, 0, 8, 2, 12, 5, 12, 12, 0, 1, 18, 2, 20, 16, 18, 4, 24, 9, 16, 16, 28, 13, 4, 16, 0, 0, 2, 0, 36, 1, 6, 4, 40, 1, 32, 2, 40, 37, 36, 8, 48, 16, 34, 32, 48, 17, 52, 36, 56, 40, 40, 26, 20, 29, 48, 52, 0, 0, 64, 2, 4, 0, 64, 4, 64, 1, 8, 10, 68, 0, 68, 8, 80, 16, 18, 2, 80, 20, 66, 20, 88, 9, 80
OFFSET
1,3
FORMULA
a(n) = A318468(n)/2.
a(n) = n - A324658(n).
MATHEMATICA
Array[BitAnd[2*#, DivisorSigma[1, #]]/2 &, 100] (* Paolo Xausa, Mar 11 2024 *)
PROG
(PARI) A324659(n) = (bitand(2*n, sigma(n))/2);
CROSSREFS
Cf. A324652 (fixed points).
Sequence in context: A059299 A332673 A128722 * A304485 A289537 A323837
KEYWORD
nonn,look
AUTHOR
Antti Karttunen, Mar 14 2019
STATUS
approved