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A283987 a(n) = A002487(n-1) XOR A002487(n), where XOR is bitwise-xor (A003987). 7
1, 0, 3, 3, 2, 1, 1, 2, 5, 7, 6, 7, 7, 6, 7, 5, 4, 1, 3, 4, 11, 13, 2, 5, 5, 2, 13, 11, 4, 3, 1, 4, 7, 3, 12, 13, 15, 12, 13, 9, 8, 3, 5, 8, 9, 11, 14, 11, 11, 14, 11, 9, 8, 5, 3, 8, 9, 13, 12, 15, 13, 12, 3, 7, 6, 1, 13, 14, 11, 7, 4, 9, 11, 4, 25, 21, 22, 27, 7, 14, 13, 5, 24, 27, 29, 24, 31, 23, 20, 29, 31, 20, 23, 25, 2, 9, 9, 2, 25, 23, 20, 31, 29, 20, 23 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
LINKS
FORMULA
a(n) = A002487(n-1) XOR A002487(n), where XOR is bitwise-xor (A003987).
a(n) = A283986(n) - A283988(n).
a(n) = A007306(n) - 2*A283988(n).
a(n) = A283977((2*n)-1).
MATHEMATICA
a[0] = 0; a[1] = 1; a[n_] := If[EvenQ@ n, a[n/2], a[(n - 1)/2] + a[(n + 1)/2]]; Table[BitXor[a[n - 1], a@ n], {n, 120}] (* Michael De Vlieger, Mar 22 2017 *)
PROG
(Scheme) (define (A283987 n) (A003987bi (A002487 (- n 1)) (A002487 n))) ;; Where A003987bi implements bitwise-XOR (A003987).
(PARI) A(n) = if(n<2, n, if(n%2, A(n\2) + A((n + 1)/2), A(n/2)));
for(n=1, 120, print1(bitxor(A(n - 1), A(n)), ", ")) \\ Indranil Ghosh, Mar 23 2017
(Python)
from functools import reduce
def A283987(n): return sum(reduce(lambda x, y:(x[0], x[0]+x[1]) if int(y) else (x[0]+x[1], x[1]), bin(n)[-1:2:-1], (1, 0)))^sum(reduce(lambda x, y:(x[0], x[0]+x[1]) if int(y) else (x[0]+x[1], x[1]), bin(n-1)[-1:2:-1], (1, 0))) if n>1 else 1 # Chai Wah Wu, May 05 2023
CROSSREFS
Odd bisection of A283977.
Cf. A283973 (positions where coincides with A007306, or equally, with A283986).
Sequence in context: A016455 A278702 A060574 * A286443 A075522 A186144
KEYWORD
nonn,base
AUTHOR
Antti Karttunen, Mar 21 2017
STATUS
approved

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Last modified April 25 07:07 EDT 2024. Contains 371964 sequences. (Running on oeis4.)