A226472 Numbers n such that n^2 XOR triangular(n) is a perfect square. XOR is the bitwise logical exclusive-or operator.

0, 1, 6, 8, 4086, 24136, 162297, 7868054, 29792904, 22666693375

Offset

1,3

Comments

Indices of perfect squares in A226470. No other terms below 2^35. Roots of generated squares: 0, 0, 7, 10, 2915, 29506, 149434, 6328037, 27602118, 20243443647.

Links

Table of n, a(n) for n=1..10.

Example

8^2 XOR triangular(8) = 64 XOR 36 = 100, because 100 is a perfect square, 8 is in the sequence.

Prog

(C)
#include <stdio.h>
#include <math.h>
int main() {
  for (unsigned long long a, r, n=0; n < (1ULL<<32); ++n) {
    a = (n*n) ^ (n*(n+1)/2);
    r = sqrt(a);
    if (r*r==a)  printf("%llu, ", n);
  }
  return 0;
}

Crossrefs

Cf. A000217, A000290, A226470, A221643.

Sequence in context: A027721 A264518 A259129 * A331480 A196762 A078196

Adjacent sequences: A226469 A226470 A226471 * A226473 A226474 A226475

Keyword

nonn,more,base

Author

Alex Ratushnyak, Jun 08 2013

Status

approved