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%I #16 Jul 24 2022 10:22:09
%S 0,1,2,3,4,5,7,8,9,12,14,15,16,17,20,21,23,24,28,32,33,34,35,36,41,45,
%T 47,48,49,56,57,60,62,63,64,65,68,73,77,79,80,84,89,92,96,97,98,99,
%U 105,112,113,117,119,120,128,129,132,136,137,140,142,143,144,153,161,164
%N Nonnegative numbers of the form x^2-2^y.
%F {n: A247763(n) > 0 }. - _R. J. Mathar_, Jul 24 2022
%e 5 is in the sequence because 5 can be written as 3^2-2^2
%t max = 200; Clear[f]; f[m_] := f[m] = Select[Table[x^2 - 2^y, {y, 0, m}, {x, Floor[2^(y/2)], Ceiling[Sqrt[2^y + max]]}] // Flatten // Union, 0 <= # <= max &]; f[1]; f[m = 2]; While[f[m] != f[m/2], m = 2 m]; Print["m = ", m]; A051204 = f[m] (* _Jean-François Alcover_, May 13 2017 *)
%Y Cf. A051213.
%K nonn
%O 1,3
%A _David W. Wilson_
%E Corrected by _Henry Bottomley_, Jul 24 2000