cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A324867 a(n) = A156552(n) XOR A324865(n), where XOR is bitwise-xor, A003987.

Original entry on oeis.org

0, 1, 3, 2, 7, 4, 15, 6, 0, 13, 31, 10, 63, 16, 2, 6, 127, 12, 255, 18, 7, 46, 511, 22, 28, 82, 4, 46, 1023, 30, 2047, 30, 54, 174, 2, 22, 4095, 256, 12, 54, 8191, 36, 16383, 66, 24, 798, 32767, 46, 60, 31, 248, 130, 65535, 28, 19, 70, 12, 1300, 131071, 42, 262143, 2734, 48, 22, 126, 94, 524287, 302, 774, 40, 1048575, 38, 2097151, 4354, 10
Offset: 1

Views

Author

Antti Karttunen, Mar 18 2019

Keywords

Crossrefs

Programs

  • PARI
    A156552(n) = {my(f = factor(n), p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res}; \\ From A156552
    A318457(n) = bitxor(n,sigma(n)-n);
    A324867(n) = if(1==n,0,A318457(A156552(n)));
    
  • PARI
    A324867(n) = { my(k=A156552(n)); bitxor(k,(A323243(n)-k)); }; \\ Needs also code from A323243.

Formula

a(1) = 0; for n > 1, a(n) = A318457(A156552(n)).
a(n) = A156552(n) XOR (A323243(n) - A156552(n)).
a(n) = A323243(n) - 2*A324398(n).