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A221643 Numbers k such that k^2 XOR (k+1)^2 is a square, where XOR is the bitwise XOR operator.

%I A221643 #29 May 03 2021 15:38:02
%S A221643 0,3,4,23,24,43,44,76,111,112,115,139,164,180,183,248,264,323,327,348,
%T A221643 411,479,480,499,611,699,747,787,943,976,1072,1103,1111,1176,1268,
%U A221643 1388,1447,1576,1684,1851,1983,1984,2008,2243,2692,3271,3383,3452,3464,3532,3679,3804,3867
%N A221643 Numbers k such that k^2 XOR (k+1)^2 is a square, where XOR is the bitwise XOR operator.
%o A221643 (Python)
%o A221643 import math
%o A221643 for i in range(1<<16):
%o A221643     s = (i*i) ^ ((i+1)*(i+1))
%o A221643     t = int(math.sqrt(s))
%o A221643     if s == t*t:
%o A221643         print(str(i), end=',')
%Y A221643 Cf. A145827, A001737.
%K A221643 nonn,base
%O A221643 1,2
%A A221643 _Alex Ratushnyak_, Mar 27 2013