A262028 a(n) = (A262026(n) - 1)/2.

0, 1, 0, 1, 0, 19, 2, 0, 2, 136, 1, 0, 1, 265, 3, 0, 3, 34, 0, 2983, 206, 1, 4, 0, 4, 1, 10, 82, 2, 0, 11209, 2, 46, 52, 5, 0, 5, 209887, 25, 463, 10, 1, 3289414, 0, 70317346, 1, 52, 28, 2509567, 6, 0, 6, 76, 7, 156595

Offset

1,6

Comments

This is the column Y_0 of the Table of a proof given as a W. Lang link under A007970.

(x0(n), y0(n) = 2*a(n) + 1) with x0(n) = A262067(n) are the fundamental solutions of the Pell equation x^2 - d*y^2 = +1 with odd y. The d values coincide with d = d(n) = A007970(n). For a proof see the mentioned link.

Links

Table of n, a(n) for n=1..55.

Formula

A262067(n)^2 - A007970(n)*(2*a(n) + 1)^2 = +1, n >= 1.

Example

For the first triples [d(n), x0(n), 2*a(n) + 1] see A262066.

Crossrefs

Cf. A006970, A262026, A262067.

Sequence in context: A210938 A223521 A018939 * A326475 A040356 A040355

Adjacent sequences: A262025 A262026 A262027 * A262029 A262030 A262031

Keyword

nonn

Author

Wolfdieter Lang, Oct 04 2015

Status

approved