A176562 a(n) = A175341(n)/4.

0, 1, 2, 4, 8, 12, 18, 22, 30, 38, 48, 56, 66, 78, 96, 110, 120, 136, 154, 168, 192, 208, 232, 250, 278, 298, 320, 346, 372, 396, 426, 454, 490, 518, 556, 586, 620, 650, 688, 728, 766, 796, 840, 870, 924, 964, 1004, 1044, 1098, 1144, 1194, 1244, 1296, 1340, 1392, 1440

Offset: 0

Author

Jaume Oliver Lafont, Apr 20 2010

Keywords

• nonn

Links

• Seiichi Manyama, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A175341, A305117.

Programs

Maple

A175341 := proc(n) local a,x,y ; a := 0 ; for x from -n to n do for y from -n to n do if x^2+y^2 <= n^2 and gcd(x,y) = 1 then a := a+1 ; end if; end do: end do: a ; end proc: seq(A175341(n)/4,n=0..40) ; # R. J. Mathar, Apr 20 2010

Mathematica

a89[n_] := a89[n] = Product[{p, e} = pe; Which[p < 3 && e == 1, 1, p == 2 && e > 1, 0, Mod[p, 4] == 1, 2, Mod[p, 4] == 3, 0, True, a89[p^e]], {pe, FactorInteger[n]}];
b[n_] := b[n] = If[n == 0, 0, b[n-1] + 4 a89[n]];
a[n_] := b[n^2]/4;
Table[a[n], {n, 0, 100}] (* Jean-François Alcover, Aug 02 2023 *)

Formula

a(n) = A305117(n^2). - Seiichi Manyama, May 26 2018

Extensions

More terms from Seiichi Manyama, May 25 2018