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A225207
Number of primitive Pythagorean quadruples (a, b, c, d) with d < 10^n.
2
4, 347, 34163, 3412143, 341175325, 34117055318, 3411700692939, 341170025540426, 34117002022924247
OFFSET
1,1
COMMENTS
a(n) ~ (1+G)*A225206(n)/Pi, where G is Catalan's constant (A006752).
EXAMPLE
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.
CROSSREFS
KEYWORD
more,nonn
AUTHOR
EXTENSIONS
a(4) from Giovanni Resta, May 01 2013
a(5)-a(9) from Max Alekseyev, Feb 28 2023
STATUS
approved