A259913 Discriminant of the number field containing the number with periodic continued fraction [1,n,1,n,1,n,...].

5, 12, 21, 8, 5, 60, 77, 24, 13, 140, 165, 12, 221, 28, 285, 5, 357, 44, 437, 120, 21, 572, 69, 168, 29, 780, 93, 56, 957, 1020, 1085, 8, 1221, 1292, 1365, 40, 1517, 1596, 1677, 440, 205, 1932, 2021, 33, 5, 92, 2397, 156, 53, 12, 2805, 728, 3021, 348, 3245

Offset: 1

Author

Clark Kimberling, Jul 20 2015

Keywords

• nonn
• easy

Comments

a(n) is the first term in row n of the triangle at A259911.

It appears that a(n) = 5 if n is a nonzero term of A004146.

Examples

			[1,3,1,3,1,3,...] = (1/6)(3 + sqrt(21)), so that a(3) = 21.
		

Links

• Clark Kimberling, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A259911.

Programs

Mathematica

v = Table[FromContinuedFraction[{1, {n, 1}}], {n, 1, 60}];
Flatten[NumberFieldDiscriminant[v]]