A345427 For 1<=x<=n, 1<=y<=n, write gcd(x,y) = u*x+v*y with u,v minimal; a(n) = sum of the values of v.

1, 3, 5, 8, 10, 14, 15, 20, 21, 24, 26, 33, 27, 34, 35, 38, 41, 41, 33, 45, 37, 41, 46, 63, 36, 31, 31, 25, 35, 50, 39, 56, 23, 15, 25, 14, -6, 8, -5, -3, -6, 3, -49, 6, -6, -15, -8, -9, -78, -124, -112, -100, -118, -122, -133, -109, -110, -139, -127, -117, -237, -166, -185, -218, -171, -215

Offset: 1

Author

N. J. A. Sloane, Jun 22 2021

Keywords

• sign

Comments

Minimal means minimize u^2+v^2. We follow Maple, PARI, etc., in setting u=0 and v=1 when x=y.

Crossrefs

Cf. A345415-A345428.

Programs

Mathematica

T[x_, y_] := T[x, y] = Module[{u, v}, MinimalBy[{u, v} /. Solve[u^2 + v^2 <= x^2 + y^2 && u*x + v*y == GCD[x, y], {u, v}, Integers], #.# &]];
a[n_] := a[n] = Sum[T[x, y][[1, 2]], {x, 1, n}, {y, 1, n}];
Table[Print[n, " ", a[n]]; a[n], {n, 1, 62}] (* Jean-François Alcover, Mar 28 2023 *)

Python

from sympy.core.numbers import igcdex
def A345427(n): return sum(v for u, v, w in (igcdex(x,y) for x in range(1,n+1) for y in range(1,n+1))) # Chai Wah Wu, Jun 22 2021