A054151 Number of positive integers <= 2^n of form x^2 + 7 y^2.

1, 1, 2, 4, 7, 12, 21, 39, 69, 130, 240, 451, 854, 1620, 3101, 5941, 11443, 22080, 42724, 82835, 160914, 313149, 610230, 1190802, 2326448, 4550161, 8908095, 17455391, 34232368, 67184426, 131949378, 259313689, 509925468, 1003302084

Offset

0,3

Links

Table of n, a(n) for n=0..33.

Index entries for sequences related to populations of quadratic forms

Crossrefs

Cf. A020670.

Sequence in context: A190168 A288133 A005126 * A018176 A374729 A372540

Adjacent sequences: A054148 A054149 A054150 * A054152 A054153 A054154

Keyword

nonn

Author

David W. Wilson

Status

approved