A236572 Value of y for solution of 5^n = x^2 + y^2 with closest x and y (n >= 0, 0 <= x < y).

1, 2, 4, 10, 20, 41, 100, 205, 500, 1025, 2500, 5125, 11753, 25625, 58765, 128125, 293825, 640625, 1469125, 3203125, 7345625, 16015625, 34867797, 80078125, 174338985, 400390625, 871694925, 2001953125, 4358474625, 10009765625, 21792373125, 50048828125

Offset

0,2

Comments

Corresponding values of x: 0,1,3,5,15,38,75,190,375,950,1875,4750,10296 (A236571).

Links

Table of n, a(n) for n=0..31.

Mathematica

m = 30; Join[{1, 2}, Table[Reduce[{5^n== x^2+y^2, 0 ≤ x ≤ y}, {x, y}, Integers][[-1, 1, 2]], {n, 2, m}]]

Crossrefs

Cf. A121705, A236571.

Sequence in context: A239346 A004647 A265096 * A283213 A283251 A318975

Adjacent sequences: A236569 A236570 A236571 * A236573 A236574 A236575

Keyword

nonn

Author

Zak Seidov, Jan 29 2014

Status

approved