A334042 Write n^2 in binary, interchange 0's and 1's, convert back to decimal.

1, 0, 3, 6, 15, 6, 27, 14, 63, 46, 27, 6, 111, 86, 59, 30, 255, 222, 187, 150, 111, 70, 27, 494, 447, 398, 347, 294, 239, 182, 123, 62, 1023, 958, 891, 822, 751, 678, 603, 526, 447, 366, 283, 198, 111, 22, 1979, 1886, 1791, 1694, 1595, 1494, 1391, 1286, 1179

Offset

0,3

Links

Daniel Starodubtsev, Table of n, a(n) for n = 0..10000

Formula

a(n) = A035327(A000290(n)). - Alois P. Heinz, Apr 13 2020

Maple

a:= n-> (l-> add((1-l[i])*2^(i-1), i=1..nops(l)))(convert(n, base, 2)):
seq(a(n), n=0..60);  # Alois P. Heinz, Apr 13 2020

Mathematica

a[n_] := FromDigits[1 - IntegerDigits[n^2, 2], 2]; Array[a, 55, 0] (* Amiram Eldar, Apr 13 2020 *)

Prog

(Python)
def oppsquare(n):
    s = str(bin(n**2))[2:]
    t = ''
    for i in range(len(s)):
        if s[i] == '0':
            t += '1'
        else:
            t += '0'
    return int(t, 2)
(PARI) a(n)=if(n, my(s=n^2); bitneg(s, exponent(s)+1), 1) \\ Charles R Greathouse IV, Apr 13 2020
(Python)
def A334042(n):
    return 2**(len(bin(n**2))-2)-1-n**2 # Chai Wah Wu, Apr 13 2020

Crossrefs

Cf. A000290, A035327.

Sequence in context: A058141 A144654 A132279 * A066107 A162276 A261955

Adjacent sequences: A334039 A334040 A334041 * A334043 A334044 A334045

Keyword

nonn,base,easy

Author

Christoph Schreier, Apr 13 2020

Status

approved