A224773 One half of the even terms of A224771.

7, 13, 15, 19, 21, 23, 25, 27, 31, 33, 35, 37, 39, 43, 45, 47, 49, 53, 55, 57, 59, 61, 63, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99, 101, 103, 105, 107, 109, 111, 113, 115, 117, 119, 121, 123, 125, 127, 129, 131, 133, 135, 137, 139

Offset

1,1

Comments

2*a(n), n >= 1, gives all even numbers representable as a primitive sum of three distinct nonzero squares.

The numbers a(n) are of interest in a problem related to integer solutions for the curvatures of the Descartes-Steiner circle theorem.

Links

Table of n, a(n) for n=1..60.

Eric Weisstein's World of Mathematics, Descartes Circle Theorem.

Formula

a(n) is one half of the n-th even term of A224771.

Example

a(1) = 7 because the first even term of A224771 is 14 (m = 1).
a(9) = 31 because 62 is the ninth even term of A224771 (m = 18).

Crossrefs

Cf. A224771.

Sequence in context: A380604 A135054 A076701 * A349749 A076196 A330431

Adjacent sequences: A224770 A224771 A224772 * A224774 A224775 A224776

Keyword

nonn

Author

Wolfdieter Lang, Apr 19 2013

Status

approved