A054153 - OEIS

%I #11 Jan 24 2022 03:56:57

%S 1,1,2,2,6,8,18,30,57,103,194,360,682,1292,2464,4721,9078,17481,33808,

%T 65485,127116,247179,481426,938950,1833572,3584679,7015237,13741715,

%U 26940645,52858250,103785060,203913141,400891200,788601863,1552114600

%N Number of positive integers <= 2^n of form x^2 + 9 y^2.

%H <a href="/index/Qua#quadpop">Index entries for sequences related to populations of quadratic forms</a>

%Y Cf. A020672.

%K nonn

%O 0,3

%A _David W. Wilson_