A232771 Values of x satisfying x^2 = floor(y^2/3 + y).

0, 1, 3, 6, 17, 43, 84, 237, 599, 1170, 3301, 8343, 16296, 45977, 116203, 226974, 640377, 1618499, 3161340, 8919301, 22542783, 44031786, 124229837, 313980463, 613283664, 1730298417, 4373183699, 8541939510, 24099948001

Offset

1,3

Comments

Corresponding values of y are given by A232765.

a(n) are also the values of x satisfying x^2 = floor(y^2/3 - y).

Let b(n) equal the second differences of a(n), where b(1) = 1, then b(3n-2) = b(3n-1) = A028230(n) and b(3n) = A067900(n) for n>0.

Links

Table of n, a(n) for n=1..29.

Formula

Empirical g.f.: x^2*(x^4+3*x^3+6*x^2+3*x+1) / (x^6-14*x^3+1). - Colin Barker, Dec 30 2014

Crossrefs

Cf. A232765, A028230, A067900.

Sequence in context: A212421 A238428 A363387 * A129905 A143363 A216878

Adjacent sequences: A232768 A232769 A232770 * A232772 A232773 A232774

Keyword

nonn

Author

Richard R. Forberg, Nov 30 2013

Status

approved