A225207 Number of primitive Pythagorean quadruples (a, b, c, d) with d < 10^n.

4, 347, 34163, 3412143, 341175325, 34117055318, 3411700692939, 341170025540426, 34117002022924247

Offset: 1

Author

Arkadiusz Wesolowski, May 01 2013

Keywords

• more
• nonn

Comments

a(n) ~ (1+G)*A225206(n)/Pi, where G is Catalan's constant (A006752).

Examples

			a(1) = 4 because there are four primitive solutions (a, b, c, d) as follows: (1, 2, 2, 3), (2, 3, 6, 7), (1, 4, 8, 9), (4, 4, 7, 9) with d < 10.
		

Links

• Wikipedia, Pythagorean quadruple

Crossrefs

Cf. A096907-A096910, A225206.

Extensions

a(4) from Giovanni Resta, May 01 2013

a(5)-a(9) from Max Alekseyev, Feb 28 2023