A247763 The number of representations of n as n=x^2-2^y, x>0, y>=0.

1, 1, 1, 1, 1, 0, 1, 2, 1, 0, 0, 1, 0, 1, 1, 1, 4, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 1, 0, 0, 0, 2, 2, 1, 1, 1, 0, 0, 0, 0, 2, 0, 0, 0, 1, 0, 1, 2, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 1, 2, 0, 0, 4, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 2, 0, 0, 0, 1

Offset: 1

Author

R. J. Mathar, Oct 19 2014

Keywords

• nonn

Comments

The n for which the count is nonzero are listed in A051204.

Links

• R. J. Mathar, Table of n, a(n) for n = 1..136
• Maohua Le, On the number of solutions of the generalized Ramanujan-Nagell equation x^2-d=2^(n+2), Acta Arithm. 60 (1991) 149.
• R. J. Mathar, The number of representations of n of the form n=x^2-2^y [PDF]
• Nicholas Tzanakis, On the diophantine equation y^2-d=2^k, J. Number Theory 17 (1983) 144.

Crossrefs

Cf. A051205.