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A224915
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a(n) = Sum_{k=0..n} n XOR k where XOR is the bitwise logical exclusive-or operator.
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6
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0, 1, 5, 6, 22, 23, 27, 28, 92, 93, 97, 98, 114, 115, 119, 120, 376, 377, 381, 382, 398, 399, 403, 404, 468, 469, 473, 474, 490, 491, 495, 496, 1520, 1521, 1525, 1526, 1542, 1543, 1547, 1548, 1612, 1613, 1617, 1618, 1634, 1635, 1639, 1640, 1896, 1897, 1901, 1902, 1918
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,3
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LINKS
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FORMULA
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a(n) = Sum_{j=1..n} 4^(v_2(j)), where v_2(j) is the exponent of highest power of 2 dividing j. - Ridouane Oudra, Jun 08 2019
a(n) = n + 3*Sum_{j=1..floor(log_2(n))} 4^(j-1)*floor(n/2^j), for n>=1. - Ridouane Oudra, Dec 09 2020
a(2*n+b) = 4*a(n) + n + b where b = 0 or 1.
(End)
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EXAMPLE
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a(2) = (0 xor 2) + (1 xor 2) = 2 + 3 = 5.
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MAPLE
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read("transforms"):
XORnos(n, k) ;
end proc:
# second Maple program:
with(MmaTranslator[Mma]):
seq(add(BitXor(n, i), i=0..n), n=0..60); # Ridouane Oudra, Dec 09 2020
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MATHEMATICA
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PROG
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(Python)
for n in range(59):
s = 0
for k in range(n): s += n ^ k
print(s, end=', ')
(Python)
(PARI) a(n) = sum(k=0, n, bitxor(n, k)); \\ Michel Marcus, Jun 08 2019
(PARI) a(n) = (3*fromdigits(binary(n), 4) - n) >>1; \\ Kevin Ryde, Dec 17 2021
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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